Related Terms

• Acute lymphocytic leukemia, acute myelogenous leukemia, acute nonlymphocytic leukemia, ALL, AML, anemia, ataxia telangiectasia, benzene, Bloom's syndrome, bone marrow, chemotherapy, chronic lymphocytic leukemia, chronic myelogenous leukemia, chronic myelomonocytic leukemia, CLL, CML, computed tomography, CT, cytogenetic analysis, erythrocytes, Fanconi's anemia, hairy cell leukemia, hematopoietic, HTLV-I, human T-cell leukemia virus I, leukemic, leukocytes, lymphocytic, lymphoid tissue, malignant, myelogenous, myeloid cells, oncogenes, petechia, platelets, radiation therapy, radionuclide scan, relapse, remission, spleen, splenectomy, thrombocytosis, tumor suppressor, ultrasound, white blood cells, X-ray.

Background

• Leukemia is cancer of the bone marrow and blood. The bone marrow is the soft, inner part of the bones that makes red and white blood cells. Leukemia is characterized by the uncontrolled accumulation of white blood cells (leucocytes).

• Under normal circumstances, the blood-forming (hematopoietic) cells of the bone marrow make leukocytes to defend the body against infectious organisms, such as viruses and bacteria. Leukocytes fight infection through a process known as phagocytosis. During phagocytosis, the leukocytes surround and destroy foreign organisms. White blood cells also produce, transport, and distribute antibodies as part of the body's immune response. If some leukocytes are damaged and remain in an immature form, they become poor infection fighters that multiply excessively and do not die off as they should. Immature leukocytes are those that have just been formed in the bone marrow.

• These damaged leukemic cells accumulate and lessen the production of oxygen-carrying red blood cells (erythrocytes), blood-clotting cells (platelets), and normal leukocytes. If untreated, the surplus leukemic cells overwhelm the bone marrow, enter the bloodstream, and eventually invade other parts of the body, such as the lymph nodes, spleen, liver, and central nervous system (brain, spinal cord). In this way, the behavior of leukemia is different than that of other cancers, which usually begin in major organs and ultimately spread to the bone marrow.

• Leukemia can be acute (fast growing) or chronic (slow growing).

• The four major types of leukemia are: acute lymphocytic leukemia (ALL); chronic lymphocytic leukemia (CLL); acute myelogenous leukemia (AML); and chronic myelogenous leukemia (CML).

• Leukemia is often thought to be a childhood disease, but statistically, leukemia strikes 10 times more adults than children. The American Cancer Society (ACS) predicts that about 35,070 new leukemia cases will be diagnosed in the United States in 2006. Acute myelogenous leukemia (AML) is the most frequently reported form of leukemia in adults, and approximately 11,930 new cases are anticipated in 2006.

• The relative five-year survival rate has more than tripled in the past 47 years for patients with leukemia due to advances in treatment. The overall relative survival rate is nearly 50%. The relative survival rates differ according to the age of the patient at diagnosis, gender, race, and type of leukemia.

• It is anticipated that approximately 21,790 deaths in the United States will be attributed to leukemia in 2007 (12,320 males and 9,470 females).

• The goal of treatment for leukemia is to bring about a complete remission. Complete remission means that there is no evidence of the disease and the individual returns to good health with normal blood and marrow cells. The cancer is not detectable in remission. Relapse indicates a return of the cancer cells and return of other signs and symptoms of the disease. Treatment centers report increasing numbers of patients with leukemia who are in complete remission at least five years after the diagnosis of their disease.

Types of Leukemia

• Leukemia is divided into four categories. It can be myelogenous or lymphocytic and acute (fast growing) or chronic (slow growing). Acute leukemia is fast-growing and can overrun the body within a few weeks or months. By contrast, chronic leukemia is slow-growing and progressively worsens over years. The terms myelogenous or lymphocytic denote which type of white blood cell is involved.

• Acute myelogenous leukemia (AML): Acute myelogenous leukemia (AML), also called acute nonlymphocytic leukemia, is the most common type of leukemia. AML occurs in children and adults. AML is fast growing and requires aggressive treatment.

• Acute lymphocytic leukemia (ALL): Acute lymphocytic leukemia (ALL) is the most common type of leukemia in young children. ALL accounts for 80% of all childhood leukemias. ALL is also fast growing and requires aggressive treatment.

• Chronic lymphocytic leukemia (CLL): Chronic lymphocytic leukemia (CLL) is a common adult leukemia. CLL is more common in Jewish people of Russian or Eastern European descent. It almost never affects children. Individuals with CLL may be well for years without treatment.

• Chronic myelogenous leukemia (CML): Chronic myelogenous leukemia (CML) is a type of leukemia that mainly affects adults. CML is associated with a chromosome abnormality called the Philadelphia chromosome, which creates an abnormal gene called BCR-ABL. The BCR-ABL gene produces an abnormal protein called tyrosine kinase that doctors and researchers believe causes leukemia cells to grow and develop. Before treatment, an individual with CML may have few or no symptoms for months or years before entering a phase in which the leukemia cells grow more quickly.

• Other chronic myeloid disorders: Like CML, this group of diseases causes chronic leukemia by the creation of too few or too many myeloid cells (a type of white blood cell). Chronic myeloid disorders include myelodysplastic syndromes and myeloproliferative disorders such as essential thrombocythemia, polycythemia vera, and myelofibrosis. These conditions may cause fluctuations in white blood cell levels and lead to acute myeloid leukemia (AML).

• Acute vs. chronic leukemia: Acute leukemia is a rapidly progressing disease that results in the accumulation of immature leukocytes (white blood cells) in the marrow and blood. The marrow often can no longer produce enough normal red blood cells, white blood cells, and platelets. Anemia, a deficiency of red cells, develops in virtually all leukemia patients. The lack of normal white cells impairs the body's ability to fight infections. A shortage of platelets results in bruising and easy bleeding.

• Therefore, acute leukemia needs to be treated immediately; otherwise, the disease may be fatal within a few months. Fortunately, some subtypes of acute leukemia respond very well to available therapies and they are curable. Children often develop acute forms of leukemia, which are managed differently from leukemia in adults.

• Chronic leukemia progresses more slowly and allows greater numbers of more mature, functional cells to be made. Unlike acute leukemia, chronic leukemia does not always require treatment. For older adults or people with early-stage CLL and few troublesome symptoms, the risks associated with the disease do not warrant the risks and discomfort associated with treatment, such as nausea, fatigue, and infection. If symptoms change or worsen, the individual can discuss treatment options with their doctor.

Causes and Risk Factors

• Age: Approximately 60-70% of leukemia cases occur in individuals who are older than 50. The most common form of leukemia among children under 19 years of age is ALL. The incidence of ALL among one to four-year-old children is more than 9 times greater than the rate for young adults ages 20-24.

• Gender: Incidence rates for all types of leukemia are higher among males than among females. Males account for more than 56% of the cases of leukemia. This may be hormonally related.

• Radiation exposure: The risk of chronic myelogenous leukemia (CML) is increased among individuals who have been exposed to high doses of radiation. Radiation damages bone cells and may cause cancerous cells to develop. Atomic bomb survivors in Japan, those who lived near the nuclear reactor accident in Chernobyl, and armed forces who participated in American nuclear detonations during the late 1950s are examples of groups exposed to high levels of radiation. It is important to note, however, that standard diagnostic X-rays pose little or no increase in leukemia risk.

• Chemicals: The risk for acute leukemia is increased 20 times among workers with long-term exposure to benzene. Risk also is increased among workers exposed to some other solvents, herbicides, and pesticides. Agricultural chemicals, in particular, have been linked with an increased risk of chronic lymphocytic leukemia (CLL). In addition, some reports suggest that leukemia risk may be increased in workers in factories exposed to dioxin, styrenes, butadienes, or ethylene oxides.

• Viruses: The human T-cell leukemia virus I (HTLV-I) is related to acute T-cell leukemia. This type of leukemia is well documented in parts of the Caribbean and Asia, but it is uncommon in the United States and Europe. Higher rates of leukemia have also been reported in workers who are exposed to animal viruses, such as butchers, slaughterhouse workers, and veterinarians.

• Genetics: Studies have reported that in some types of leukemia, such as AML, genetics also may play a role in the risk for recurrence of the disease. Leukemia risk is increased 15 times among children with Down's syndrome, which is a genetically linked chromosomal abnormality (usually an extra copy of chromosome 21). Three rare inherited disorders, including Fanconi's anemia, Bloom's syndrome, and ataxia telangiectasia, also have an increased risk for leukemia.

• Race: Leukemia varies among racial and ethnic groups with different genetic make-ups. For example, rates of lymphoma and leukemia, such as chronic lymphocytic leukemia (CLL), are especially high in some Jewish populations, whereas Asian populations rarely develop CLL. First-degree relatives, including parents, children, and siblings of CLL patients, have two to four times the risk for leukemia due to genetics.

• Leukemia is one of the top 15 most frequently occurring cancers in minority groups.

• Cigarette smoking: Cigarette smoking is a known lifestyle-related risk factor for leukemia. Potential leukemia-causing chemicals in tobacco smoke include benzene, polonium-210, and polycyclic aromatic hydrocarbons (PAHs). These carcinogens (cancer-causing substances) are absorbed by the lungs and are spread via the bloodstream. It is estimated that one in four cases of acute myelogenous leukemia (AML) is the result of cigarette smoking.

• Cancer therapy: Individuals who have received chemotherapy and radiation therapy for previous cancers have a slightly greater chance of getting secondary leukemia (leukemia that arises after therapy). Acute myelogenous leukemia (AML) has been reported after chemotherapy and/or radiotherapy for various solid tumors (such as breast cancer and ovarian cancer), blood malignancies, and non-malignant conditions. The chemotherapeutic agents most often associated with secondary leukemias are procarbazine, chlorambucil, etoposide, mechlorethamine, teniposide, and cyclophosphamide. The risk is increased when these drugs are combined with radiation therapy. Many secondary leukemias are AMLs that develop within nine years after treatment of Hodgkin's disease, non-Hodgkin's lymphoma, or childhood CLL. Further chemotherapy often is ineffective in patients with secondary AML. Their prognosis is less favorable than that of typical AML patients.

• Other causes: The use of the antibiotic chloramphenicol has been linked with the development of childhood leukemia. Chloramphenicol is rarely used today. Other medications, such as growth hormones and phenylbutazone, also have reportedly shown some associations with leukemia. Leukemias and lymphomas have been observed in recipients of organ transplants, and certain immunodeficiency syndromes are associated with leukemias.

Signs and Symptoms

• Leukemia cells are abnormal cells that cannot do what normal blood cells do. They cannot help the body fight infections. For this reason, individuals with leukemia often get infections and have fevers. Also, those with leukemia often have less than the normal amount of healthy red blood cells and platelets. As a result, there are not enough red blood cells to carry oxygen through the body. With this condition, called anemia, individuals may look pale and feel weak and tired. When there are not enough platelets, patients bleed and bruise easily.

• Like all blood cells, leukemia cells travel through the body. Depending on the number of abnormal cells and where these cells collect, patients with leukemia may have a number of symptoms. Some of the common symptoms of leukemia include: fever, chills, and other flu-like symptoms; weakness and fatigue; frequent infections; loss of appetite and/or weight; swollen or tender lymph nodes, liver, or spleen; easy bleeding or bruising; tiny red spots, called petechia,under the skin; swollen or bleeding gums; sweating, especially at night; and/or bone or joint pain.

• In acute leukemia, symptoms appear and get worse quickly. In chronic leukemia, symptoms may not appear for a long time. When symptoms do appear, they generally are mild at first and get worse gradually. Doctors often find chronic leukemia during a routine checkup - before there are any symptoms - with blood tests revealing abnormal white blood cell counts.

• In acute leukemia, the abnormal cells may collect in the brain or spinal cord. The result may be headaches, vomiting, confusion, loss of muscle control, and seizures. Leukemia cells can collect in the testicles and cause swelling. Some individuals develop sores in the eyes or on the skin. Leukemia also can affect the digestive tract, kidneys, lungs, or other parts of the body.

• Chronic leukemia often goes undetected for many years until it is identified in a routine blood test. Nearly one in five chronic leukemia patients have no symptoms at the time of their diagnosis. In chronic leukemia, the abnormal blood cells may gradually collect in various parts of the body. Chronic leukemia may affect the skin, central nervous system, digestive tract, kidneys, and testicles.

Complications

• Fatigue: Leukemia can cause individuals to have too few red blood cells, resulting in anemia. Anemia can make the individual feel tired by decreasing the number of red blood cells that can carry oxygen to tissues. Treatment for leukemia, such as with chemotherapy, can also cause a drop in red blood cells, leading to fatigue.

• Excess bleeding: Blood cells called platelets help control bleeding by prompting the blood to clot. A shortage of blood platelets (thrombocytopenia) can result in easy bleeding and bruising, including frequent or severe nosebleeds, bleeding from the gums, or tiny red marks caused by bleeding into the skin.

• Pain: Leukemia can cause bone pain or joint pain as the bone marrow expands when excess white blood cells build up.

• Enlarged spleen: Some of the extra blood cells produced when an individual has leukemia are stored in the spleen, causing the spleen to become swollen or enlarged. Rarely, the spleen becomes so large that it is at risk of bursting. More commonly, the swollen spleen takes up space in the abdomen and makes the individual feel full even after small meals or causes pain on the left side of the body below the ribs and difficulty breathing.

• Stroke or excess clotting: Some individuals with CML produce too many platelets. Without treatment, this high platelet count, called thrombocytosis, can cause excessive clotting of the blood, which can lead to stroke. Stroke is neurological damage to the brain due to a lack of oxygen. An increase in blood clotting can lead to the blocking of blood vessels in the brain, decreasing the oxygen to the brain tissue and causing brain cell death.

• Infection: White blood cells help the body fight off infection. Although individuals with leukemia have too many white blood cells, these cells are often leukemic (damaged) and do not function properly. As a result, they are not able to fight infection as well as healthy white cells can. In addition, treatment can cause the white cell count to drop too low (neutropenia), also making individuals vulnerable to infection.

• Metastasis: Metastasis is the movement or spreading of cancer cells from one organ or tissue to another. Leukemic cells in the blood can deposit into organs and tissues, such as the brain and spine, causing further cancer development.

• Death: If leukemia cannot be successfully treated, it ultimately is fatal.

Diagnosis

• Once a doctor suspects that an individual's blood is abnormal, blood and bone marrow tests are performed to rule out leukemia. Additional tissue samples may be needed to confirm the diagnosis or to help plan treatment.

• If an individual has symptoms that suggest leukemia, the doctor may do a physical exam and ask about the personal and family medical history. The doctor also may order laboratory tests, including blood tests.

• Bone marrow tests: The bone marrow is sampled by a technique known as bone marrow aspiration. During this procedure, a thin, hollow needle with a syringe attachment is used to suction up (aspirate) a teaspoon-sized sample of liquid bone marrow from the back of the hip bone. A larger needle is then employed to obtain a bone marrow biopsy ("core" biopsy), which removes roughly a 1/16 inch cylindrical piece of bone marrow from the hip site. After the bone marrow samples are obtained, they are examined by many physician specialists, including a pathologist (disease diagnosis specialist, who examines samples under a microscope), hematologist (blood specialist), and oncologist (cancer specialist). The individual is generally awake during the procedure, but local anesthetics (such as lidocaine) and sedatives (such as midazolam or Versed®) may be administered. There is usually no pain involved.

• Cytogenetic analysis: Cytogenetic analysis detects changes in the chromosomes, including the presence of the Philadelphia chromosome (a genetic abnormality that can lead to leukemia). It can be done using a regular microscope or a more modern lab technology called fluorescence in situ hybridization (FISH). Blood will be drawn from the individual and analyzed for the genetic abnormality.

• X-ray: X-rays are used to see whether there are enlarged lymph nodes in the chest, localized masses in the lungs, or evidence of spreading to the outer bones or joints.

• Computerized tomography (CT): Computed tomography (CT) scan is a computer-assisted x-ray that produces cross-sectional images of the body. CT scans are not often used in leukemia patients unless the doctor suspects that the disease has spread to other organs. In such cases, CT scans may detect changes in the lymph nodes around the heart, trachea (windpipe), or abdomen. Lymph node enlargement is more common in patients with acute or chronic lymphocytic leukemia (ALL, CLL).

• Magnetic resonance imaging (MRI): Magnetic resonance imaging (MRI) scan is a procedure that uses electromagnets and radio waves to create computer-generated pictures of the internal organs. MRI may be used if the doctor suspects that leukemia involves the brain or lungs.

• Radionuclide scan: A radionuclide scan may be performed to rule out non-leukemic disorders in individuals who complain of bone pain. The radiologist injects the individual with a radioactive chemical (such as gallium-67), which will accumulate in areas of infection or malignancy and can be viewed with a special camera. This procedure is not used for individuals who already have been diagnosed with leukemia.

Treatment

• Leukemia treatment falls into two categories: treatment to fight the cancer and treatment to relieve the symptoms of the disease and the side effects of the treatment (supportive care).

• The goal of treatment for leukemia is to bring about a complete remission. Unlike other types of cancer, leukemia is not a solid tumor that a doctor can surgically remove. The source of the problem is in the bone marrow, and bone marrow cannot be removed.

• Treatment for leukemia is complex, depending on many factors including age and overall health, the type of leukemia, and whether it has spread to other parts of the body.

• In general, there are five major approaches to the treatment of leukemia: chemotherapy to kill leukemia cells using strong anti-cancer drugs; interferon therapy to slow the reproduction of leukemia cells and promote the immune system's anti-leukemia activity; radiation therapy to kill cancer cells by exposure to high-energy radiation; stem cell transplantation (SCT) to enable treatment with high doses of chemotherapy and radiation therapy; and surgery to remove an enlarged spleen or to install a venous access device (large plastic tube) to give medications and withdraw blood samples.

• Chemotherapy: Chemotherapy uses drugs to destroy cancer cells. These drugs can be given intravenously (IV, through a vein), orally (by mouth), subcutaneously (SubQ, or injected under the skin), intramuscularly (injected into muscle), or intrathecally (injected into cerebrospinal fluid).

• Chemotherapy used to treat leukemia varies, because there are many different forms of this disease. In general, leukemia treatment combines chemotherapy with a number of different anticancer drugs, which destroy cancer cells by preventing them from growing and dividing rapidly. Unfortunately, a number of the body's normal, noncancerous cells (e.g., hair cells, red and white blood cells, blood-clotting platelets, cells that line the gastrointestinal tract) also divide rapidly, and are harmed by chemotherapy. Damage to these cells causes side effects, which depend upon the type and dose of the drugs, as well as the length of time that they are used.

• If the leukemia does not respond to one or two courses of treatment, a different drug program may be used to achieve remission. A different drug program may also be used if a relapse occurs.

• Chemotherapy side effects may include: temporary hair loss; mouth sores; anemia or a decreased number of red blood cells that may cause fatigue, dizziness, and shortness of breath; leukopenia or a decreased numbers of white blood cells that may lower resistance to infection; thrombocytopenia or a decreased number of platelets that may lead to easy bleeding or bruising; and gastrointestinal symptoms, including nausea, vomiting, and diarrhea.

• Radiation therapy: Radiation therapy is used along with chemotherapy for some kinds of leukemia. Radiation therapy (also called radiotherapy) uses high-energy rays to damage cancer cells and stop them from growing.

• Radiation therapy for leukemia may be given in two ways. For some individuals, the doctor may direct the radiation to one specific area of the body where there is a collection of leukemia cells, such as the spleen or testicles. Others may receive radiation that is directed to the whole body. This is called total-body irradiation. This type of radiation usually is given before a bone marrow transplant.

• Depending on how and where the radiation is administered, it may cause certain side effects such as fatigue (extreme tiredness), loss of appetite, nausea, diarrhea, and skin problems. Radiation of lymph node areas may result in suppression of the immune system to varying degrees. Irradiation of the underlying bone and the marrow within the bone may result in suppression of the blood counts.

• Interferon therapy: Interferons are a class of proteins that are released by virus-infected cells. They help normal cells to make antiviral proteins. Interferons also help the body to reduce leukemia cell growth and reproduction, while strengthening the body's immune response. Interferon-alpha (INFa) is a type of interferon that frequently is used to treat leukemia.

• Interferon-alpha can be given by a number of methods. Subcutanous injection is the customary route. INF-a is usually offered to all newly diagnosed patients who are not candidates for stem cell transplantation. Possible IFN-a-related complaints include fevers, chills, muscle aches, bone pain, headaches, concentration difficulties, fatigue, nausea, vomiting, and general flu-like symptoms when starting the drug. Such symptoms usually last for one to two weeks, but may be lessened by drugs such as acetaminophen (Tylenol®). Side effects recur if the INF-a dosage is increased, but they are temporary and usually improve after INF-a therapy is completed.

• Stem cell transplantation: Stem cell transplantation, or bone marrow transplant, is a treatment that allows use of very high doses of chemotherapy along with total body irradiation in order to kill the leukemic cells. At the completion of high-dose therapy, the individual's immune system is essentially depleted, and they are at high risk of developing serious life-threatening infections. These individuals are treated in specially designed, sterile, air-filtered marrow transplant rooms. Stem cell transplantation is a surgical procedure performed under general anesthesia.

• Immediately upon completion of the high-dose therapy, stem cells from a healthy, complete blood cell matched donor, usually a sibling or, less commonly, a parent, are transplanted into a vein whereupon they migrate to the marrow where they grow and multiply before entering the circulation. This process may take two to three weeks to be completed. On rare occasions, when a donor is not available, one's own marrow cells, usually pretreated in order to remove residual, but otherwise unseen, leukemic cells, are infused. This approach is far less successful than the use of matched donor cells.

• If an individual receives stem cells from a matched donor, the type of stem cell transplant is called allogeneic. If the individual's own stem cells are reintroduced back into the patient following high dose therapy, the infusion is called autologous. Side effects include fever and fatigue.

• Surgery: A splenectomy is the surgical removal of the spleen. The spleen is located in the abdomen, on the left side. The spleen acts as a filtering system for blood cells. When an individual has chronic leukemia, the spleen tends to collect leukemia cells, transfused platelets (given during surgery), and red blood cells. Frequently, the spleen enlarges from storing these cells. This makes it difficult for the chemotherapy to reduce the quantity of diseased cells. If the spleen is not removed, it sometimes grows so large that it causes breathing difficulty and compresses other organs. In that case, a splenectomy may be needed. Splenectomy is used along with other treatments, such as chemotherapy and radiation.

Integrative Therapies

• Note: Although there are few studies to support the use of integrative therapies in leukemia, many of the following therapies have been reported useful in the management of cancer in general.

• Strong scientific evidence:

• Vitamin A: Vitamin A is a fat-soluble vitamin, which is derived from two sources: preformed retinoids and provitamin carotenoids. Retinoids, such as retinal and retinoic acid, are found in animal sources such as livers, kidneys, eggs, and dairy produce. Carotenoids like beta-carotene (which has the highest vitamin A activity) are found in plants such as dark or yellow vegetables and carrots. The prescription drug All-Trans-Retinoic Acid (ATRA, Vesanoid®) is a vitamin A derivative that is an established treatment for acute promyelocytic leukemia and improves median survival in this disease. Treatment should be under strict medical supervision. Vitamin A supplements should not be used simultaneously with ATRA due to a risk of increased toxicity.

• Vitamin A toxicity, or hypervitaminosis A, is rare in the general population. Vitamin A toxicity can occur with excessive amounts of vitamin A taken over short or long periods of time. Consequently, toxicity can be acute or chronic. An infant with acute toxicity can develop a bulging fontalle (the soft spot on the head) and symptoms similar to a brain tumor. Adults experience less specific symptoms such as headache, dizziness, fatigue, malaise, blurry vision, bone pain and swelling, nausea, and/or vomiting. Severe toxicity can lead to eye damage, high levels of calcium, and liver damage. Persons with liver disease and high alcohol intake may be at risk for hepatotoxicity from vitamin A supplementation. Smokers who consume alcohol and beta-carotene may be at an increased risk for lung cancer or cardiovascular disease. At recommended doses, vitamin A is generally considered non-toxic.

• Good scientific evidence:

• Greater celandine: Ukrain™, a semisynthetic drug derived from greater celandine (Chelidonium majus), has been studied in clinical trials of various types of cancer with consistently positive outcomes. However, the quality of the research performed to date is inadequate, and higher quality studies are needed.

• Use cautiously in patients taking amphetamines, morphine, hexobarbital, MAOIs, or dopaminergic or serotonergic drugs, or in patients undergoing radiation therapy. Avoid in patients with liver disease or in pregnant and lactating women.

• Guided imagery: Early research suggests that guided imagery may help reduce cancer pain. Further research is needed to confirm these results.

• Guided imagery is usually intended to supplement medical care, not to replace it, and guided imagery should not be relied on as the sole therapy for a medical problem. Contact a qualified health care provider if mental or physical health is unstable or fragile. Never use guided imagery techniques while driving or doing any other activity that requires strict attention. Use cautiously with physical symptoms that can be brought about by stress, anxiety or emotional upset because imagery may trigger these symptoms. If feeling unusually anxious while practicing guided imagery, or with a history of trauma or abuse, speak with a qualified health care provider before practicing guided imagery.

• Meditation: There is good evidence that various types of meditation may help improve quality of life in cancer patients. Studies have shown benefits for mood, sleep quality, and the stresses of treatment. The specific effects of meditation are not fully understood. Additional research is needed in this area.

• Use cautiously with underlying mental illnesses. People with psychiatric disorders should consult with their primary mental healthcare professional(s) before starting a program of meditation, and should explore how meditation may or may not fit in with their current treatment plan. Avoid with risk of seizures. The practice of meditation should not delay the time to diagnosis or treatment with more proven techniques or therapies, and should not be used as the sole approach to illnesses.

• Psychotherapy: Psychotherapy is an interactive process between a person and a qualified mental health care professional (psychiatrist, psychologist, clinical social worker, licensed counselor, or other trained practitioner). There is good evidence that psychotherapy may enhance quality of life in cancer patients by reducing emotional distress and aiding in coping with the stresses and challenges of cancer. Therapy may be supportive-expressive therapy, cognitive therapy or group therapy. While some patients seek psychotherapy in hopes of extending survival, there conclusive evidence of effects on medical prognosis is currently lacking. Psychotherapy may help people come to terms with the fact that they may die of cancer, which is the 4th stage of dealing with a terminal illness, including denial, anger, bargaining, and acceptance.

• Psychotherapy is not always sufficient to resolve mental or emotional conditions. Psychiatric medication is sometimes needed. The reluctance to seek and use appropriate medication may contribute to worsening of symptoms or increased risk for poor outcomes. In order to be successful, psychotherapy requires considerable personal motivation and investment in the process. This includes consistent attendance and attention to treatment recommendations provided by the practitioner. Not all therapists are sufficiently qualified to work with all problems. The client or patient should seek referrals from trusted sources and should also inquire of the practitioner's training and background before committing to work with a particular therapist. Some forms of psychotherapy evoke strong emotional feelings and expression. This can be disturbing for people with serious mental illness or some medical conditions. Psychotherapy may help with post-partum depression, but is not a substitute for medication, which may be needed in severe cases.

• Yoga: Yoga is an ancient system of relaxation, exercise, and healing with origins in Indian philosophy. Several studies report enhanced quality of life in cancer, lower sleep disturbance, decreased stress symptoms and changes in cancer-related immune cells after patients received relaxation, meditation and gentle yoga therapy. Yoga is not recommended as a sole treatment for cancer but may be helpful as an adjunct therapy.

• Yoga is generally considered to be safe in healthy individuals when practiced appropriately. Avoid some inverted poses with disc disease of the spine, fragile or atherosclerotic neck arteries, risk for blood clots, extremely high or low blood pressure, glaucoma, detachment of the retina, ear problems, severe osteoporosis, or cervical spondylitis. Certain yoga breathing techniques should be avoided in people with heart or lung disease. Use cautiously with a history of psychotic disorders. Yoga techniques are believed to be safe during pregnancy and breastfeeding when practiced under the guidance of expert instruction (the popular Lamaze techniques are based on yogic breathing). However, poses that put pressure on the uterus, such as abdominal twists, should be avoided in pregnancy.

• Unclear or conflicting scientific evidence:

• Acupuncture: Acupuncture, or the use of needles to manipulate the "chi" or body energy, originated in China over 5,000 years ago. There has been limited research on acupuncture for cancer pain, and the research that was done was shown to have mixed results. More studies are needed to determine potential benefits. Evidence from several small studies supports use of acupuncture at a specific point on the wrist (P6) to help chemotherapy patients reduce nausea and vomiting. Acupuncture may also reduce the pain associated with cancer.

• Needles must be sterile in order to avoid disease transmission. Avoid with valvular heart disease, infections, bleeding disorders or with drugs that increase the risk of bleeding (anticoagulants), medical conditions of unknown origin, or neurological disorders. Avoid on areas that have received radiation therapy and during pregnancy. Use cautiously with pulmonary disease (like asthma or emphysema). Use cautiously in elderly or medically compromised patients, diabetics or with history of seizures. Avoid electroacupuncture with arrhythmia (irregular heartbeat) or in patients with pacemakers.

• Aloe: Transparent gel from the pulp of the meaty leaves of Aloe vera has been used on the skin for thousands of years to treat wounds, skin infections, burns, and numerous other skin conditions. Dried latex from the inner lining of the leaf has traditionally been used as an oral laxative. Preliminary research suggests that aloe may help in the area of cancer prevention or may aid in the regression of cancerous tumors. Additional research is needed in this area.

• Caution is advised when taking aloe supplements as numerous adverse effects including a laxative effect, cramping, dehydration and drug interactions are possible. Aloe should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• American pawpaw: Evidence supporting the use of the American pawpaw (Asimina triloba) tree for cancer treatment in humans is largely anecdotal and subjective. However, use in humans has reported minimal side effects, and evidence from animal and test tube studies suggest that American pawpaw extract does have some anticancer activity. Pawpaw standardized extract has been used for 18 months in patients with various forms of cancer. Well-designed studies on the long-term effects of pawpaw extracts are currently lacking. Pawpaw should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Antineoplastons: Antineoplastons are a group of naturally occurring peptide fractions, which were observed by Stanislaw Burzynski, MD, PhD in the late 1970s to be absent in the urine of cancer patients. There is inconclusive scientific evidence regarding the effectiveness of antineoplastons in the treatment of cancer. Several preliminary human studies (case series, phase I/II trials) have examined antineoplaston types A2, A5, A10, AS2-1, and AS2-5 for a variety of cancer types. It remains unclear if antineoplastons are effective, or what doses may be safe. Until better research is available, no clear conclusion can be drawn.

• Avoid if allergic or hypersensitive to antineoplastons. Use cautiously with high medical or psychiatric risk, an active infection due to a possible decrease in white blood cells, high blood pressure, heart conditions, chronic obstructive pulmonary disease, liver disease or damage, or kidney disease or damage. Avoid if pregnant or breastfeeding.

• Arabinoxylan: Arabinoxylan is made by altering the outer shell of rice bran using enzymes from Hyphomycetes mycelia mushroom extract. Arabinoxylan has been found to improve immune reactions in patients with diabetes and cancer of various types. Arabinoxylan products may contain high calcium and phosphorus levels, which may be harmful for patients with compromised renal (kidney) function. Caution is advised when taking arabinoxylan supplements, as numerous adverse effects including drug interactions are possible. Arabinoxylan should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Aromatherapy: Healing with fragrant oils has been used for thousands of years. Aromatherapy is often used in people with chronic illnesses (frequently in combination with massage), with the intention to improve quality of life or well-being. There is currently not enough scientific evidence to form a firm conclusion about the effectiveness of aromatherapy for quality of life in cancer.

• Essential oils should only be used on the skin in areas without irritation. Essential oils should be administered in a carrier oil to avoid toxicity. Avoid with a history of allergic dermatitis. Use cautiously if driving or operating heavy machinery. Avoid consuming essential oils. Avoid direct contact of undiluted oils with mucous membranes. Use cautiously if pregnant.

• Art therapy: Art therapy involves the application of a variety of art modalities including drawing, painting, clay and sculpture. Art therapy enables the expression of inner thoughts or feelings when verbalization is difficult or not possible. Limited evidence suggests that art therapy may be of benefit in cancer caregiving for families of cancer patients. Possible benefits include reduced stress, lowered anxiety, increased positive emotions and increased positive communication with cancer patients and health care professionals. Art therapy may also reduce pain and other symptoms in cancer patients. More studies are needed to determine how best to use this form of intervention with this population. Art therapy may also benefit children hospitalized with leukemia during and after painful procedures. Limited available study suggests that art therapy improves cooperation with treatment. Children requested art therapy again when procedures were repeated, and parents reported that children were more manageable after art therapy.

• Art therapy may evoke distressing thoughts or feelings. Use under the guidance of a qualified art therapist or other mental health professional. Some forms of art therapy use potentially harmful materials. Only materials known to be safe should be used. Related clean-up materials (like turpentine or mineral spirits) that release potentially toxic fumes should only be used with good ventilation.

• Astragalus: Astragalus (Astragalus membranaceus) has been used in Chinese medicine for centuries for its immune enhancing properties. Although early laboratory and animal studies report immune stimulation and reduced cancer cell growth associated with the use of astragalus, reliable human evidence in these areas is currently lacking. In Chinese medicine, astragalus-containing herbal mixtures are also sometimes used with the intention to reduce side effects of chemotherapy and other cancer treatments. Astragalus-containing herbal combination formulas may also have beneficial effects in aplastic anemia. Due to a lack of well-designed research, a firm conclusion cannot be drawn.

• Caution is advised when taking astragalus supplements, as numerous adverse effects including drug interactions are possible. Astragalus should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Baikal skullcap: Although the outcomes of early studies using baikal skullcap for cancer are promising, high-quality clinical studies are needed in this area before a conclusion can be made. Avoid if allergic or hypersensitive to Baikal skullcap (Scutellaria barbata), its constituents, or members of the Lamiaceae family. Use cautiously if taking sedatives and/or operating heavy machinery. Use cautiously if taking antineoplastic (anticancer) agents or agents metabolized by cytochrome P450 enzymes. Avoid if pregnant or breastfeeding. Baikal skullcap is an ingredient in PC-SPES, a product that has been recalled from the U.S. market and should not be used.

• Bee pollen: Bee pollen is considered a highly nutritious food because it contains a balance of vitamins, minerals, proteins, carbohydrates, fats, enzymes, and essential amino acids. Research has found that bee pollen may reduce some adverse effects of cancer treatment side effects. Additional study is needed before a firm recommendation can be made. Caution is advised when taking bee pollen supplements as allergic reactions may occur in sensitive individuals. Bee pollen should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Beta-glucan: Treatment with a beta-glucan, called lentinan, plus chemotherapy (S-1) may help prolong the lives of patients with cancer that has returned or cannot be operated on. More research is needed in this area. Avoid if allergic or hypersensitive to beta-glucan. When taken by mouth, beta-glucan is generally considered safe. Use cautiously with AIDS or AIDS-related complex (ARC). Avoid using particulate beta-glucan. Avoid if pregnant or breastfeeding.

• Bitter melon: Bitter melon (Momordica charantia) is used in Avurvedic medicine from India to lower blood sugar levels. Research has also found that bitter melon extracts may be beneficial in cancer therapies. MAP30, a protein isolated from bitter melon extract, is reported to possess anti-cancer effects in laboratory studies. Potential anti-cancer effects have not been studied appropriately in humans. Caution is advised when taking bitter melon supplements, as numerous adverse effects including blood sugar lowering and drug interactions are possible. Bitter melon should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Black tea: Black tea (Camellia sinensis) is from the same plant as green tea, but the leaves are processed differently. Black tea usually contains more caffeine than green tea. Several studies have explored a possible association between regular consumption of black tea and rates of cancer in several populations. This research has yielded conflicting results, with some studies suggesting benefits, and others reporting no effects. Laboratory and animal studies report that components of tea, such as polyphenols, have antioxidant properties and effects against tumors. However, effects in humans remain unclear, and these components may be more common in green tea rather than in black tea. Some animal and laboratory research suggests that components of black tea may actually be carcinogenic, or cancer causing, although effects in humans are not clear. Overall, the relationship of black tea consumption and human cancer prevention remains undetermined.

• Avoid if allergic or hypersensitive to caffeine or tannins. Skin rash and hives have been reported with caffeine ingestion. Use caution with diabetes. Use cautiously if pregnant. Heavy caffeine intake during pregnancy may increase the risk of SIDS (sudden infant death syndrome). Very high doses of caffeine have been linked with birth defects. Caffeine is transferred into breast milk. Caffeine ingestion by infants can lead to sleep disturbances/insomnia. Infants nursing from mothers consuming greater than 500 milligrams of caffeine daily have been reported to experience tremors and heart rhythm abnormalities. Tea consumption by infants has been linked to anemia, decreased iron metabolism, and irritability.

• Bovine cartilage: In early study, bovine tracheal cartilage (preparations such as Catrix® and VitaCarte®) has been studied for the treatment of cancer with encouraging results. High quality clinical research is needed to better determine the effectiveness of bovine tracheal cartilage preparations for cancer treatment.

• Avoid if allergic or hypersensitive to bovine cartilage or any of its constituents. Use cautiously with cancer, renal (kidney) failure, or hepatic (liver) failure. Avoid if pregnant or breastfeeding.

• Bromelain: Bromelain is a sulfur-containing digestive enzyme (proteins which help with digestion) that is extracted from the stem and the fruit of the pineapple plant (Ananas comosus). There is not enough information to recommend for or against the use of bromelain in the treatment of cancer, either alone or in addition to other therapies. One small study found that a bromelain supplement decreased tumor size in 12 breast cancer patients. Patients took the supplements for different periods of time, lasting from months to years. Caution is advised when taking bromelain supplements, as numerous adverse effects including blood thinning and drug interactions are possible. Bromelain should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Cat's claw: Originally found in Peru, the use of cat's claw (Uncaria tomentosa) has been said to date back to the Inca civilization, possibly as far back as 2,000 years. Cat's claw has anti-inflammatory properties, and several low-quality studies suggest that cat's claw may slow tumor growth. However, this research is early and has not identified specific types of cancer that may benefit; thus, the results are not clear. A few studies suggest that cat's claw may also boost the immune system. Caution is advised when taking cat's claw supplements, as numerous adverse effects including blood thinning and drug interactions are possible. Cat's claw should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Chaparral: Chaparral was used by the Native Americans for various health conditions. The chaparral component nordihydroguaiaretic acid (NDGA) has been evaluated as a treatment for cancer but due to risk of toxicity is considered unsafe and not recommended for use. Chaparral and NDGA have been associated with cases of kidney and liver failure, liver cirrhosis, kidney cysts, and kidney cancer in humans. In response to these reports, the U.S. Food and Drug Administration (FDA) removed chaparral from its "generally recognized as safe" (GRAS) list in 1970. Chaparral and NDGA are generally considered unsafe and are not recommended for use.

• Avoid if allergic to chaparral or any of its components, including nordihydroguaiaretic acid. Use cautiously if taking blood thinners (anticoagulants), blood sugar medication, or drugs that are broken down by the liver (like amiodarone, phenobarbital, valproic acid). Stop use two weeks before surgery/dental/diagnostic procedures with bleeding risk, and do not use immediately after these procedures. Use cautiously if driving or operating heavy machinery. Avoid if pregnant or breastfeeding.

• Chlorophyll: Preliminary evidence in suggest that chlorophyll may aid in the reduction of side effects associated with photodynamic therapies, such as those used in management of malignant tumors. Further research is required to support the use of chlorophyll as a laser therapy adjunct for cancer treatment.

• Avoid if allergic or hypersensitive to chlorophyll or any of its metabolites. Use cautiously with photosensitivity, compromised liver function, diabetes or gastrointestinal conditions or obstructions. Use cautiously if taking immunosuppressant agents or antidiabetes agents. Avoid if pregnant or breastfeeding.

• Chrysanthemum: Early study indicates that hua-sheng-ping (includes Chrysanthemum morifolium, Glycyrrhiza uralensis, and Panax notoginseng) may be beneficial for patients with precancerous lesions. However, more research is needed.

• Avoid if allergic or hypersensitive to Chrysanthemum, its constituents, or members of the Asteraceae/Compositae family, such as dandelion, goldenrod, ragweed, sunflower, and daisies. Use cautiously if taking medication for gout, cancer, or HIV. Use cautiously with compromised immune systems or if taking immunomodulators. Avoid with photosensitivity or if taking photosensitizers. Avoid large acute or chronic doses of ingested pyrethrin. Avoid pyrethrin with compromised liver function, epilepsy, or asthma. Avoid ocular exposure to pyrethrin. Avoid if pregnant or breastfeeding.

• Coenzyme Q10: Further research is needed to determine if coenzyme Q10 (CoQ10) may be of benefit for cancer when used with other therapies.

• Allergy associated with Coenzyme Q10 supplements has not been reported, although rash and itching have been reported rarely. Stop use two weeks before surgery/dental/diagnostic procedures with bleeding risk and do not use immediately after these procedures. Use caution with a history of blood clots, diabetes, high blood pressure, heart attack, or stroke, or with anticoagulants (blood thinners) or antiplatelet drugs (like aspirin, warfarin, clopidogrel (like Plavix®), or blood pressure, blood sugar, cholesterol or thyroid drugs. Avoid if pregnant or breastfeeding.

• Copper: Copper is a mineral that occurs naturally in many foods, including vegetables, legumes, nuts, grains and fruits, as well as shellfish, avocado, and beef (organs such as liver). Preliminary research reports that lowering copper levels theoretically may arrest the progression of cancer by inhibiting blood vessel growth (angiogenesis). Copper intake has not been identified as a risk factor for the development or progression of cancer. Copper is potentially unsafe when used orally in higher doses than the RDA. Copper supplements should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Cranberry: Several laboratory studies have reported positive effects of proanthocyanidins, flavonoid components of cranberry (Vaccinium macrocarpon) and other fruits such as blueberries, grape seed, and pomegranate, on health. Based on early laboratory research, cranberry has been proposed for cancer prevention. Additional study is needed in humans before a conclusion can be made.

• Avoid if allergic to cranberries, blueberries or other plants of the Vaccinium species. Sweetened cranberry juice may effect blood sugar levels. Use cautiously with a history of kidney stones. Avoid more than the amount usually found in foods if pregnant or breastfeeding.

• Dandelion: Limited animal research does not provide a clear assessment of the effects of dandelion on tumor growth. Well-conducted human studies are needed to better determine dandelion's effects on cancer.

• Avoid if allergic to chamomile, feverfew, honey, yarrow, or any related plants such as aster, daisies, sunflower, chrysanthemum, mugwort, ragweed, or ragwort. Use cautiously with diabetes or bleeding disorders, gastroesophageal reflux disease (GERD), kidney or liver diseases, or a history of stroke or electrolyte disorders. Monitor potassium blood levels. Stop use two weeks before surgery/dental/diagnostic procedures with bleeding risk and do not use immediately after these procedures. Avoid if pregnant or breastfeeding.

• Echinacea: There is currently a lack of clear human evidence that echinacea affects any type of cancer. The evidence from a small number of clinical trials evaluating efficacy of echinacea in the treatment of radiation-induced leukopenia (decrease in white blood cells) is equivocal. Studies have used the combination product Esberitox®, which includes extracts of echinacea (Echinacea purpurea and pallida) root, white cedar (Thuja occidentalis) leaf, and wild indigo (Baptisia tinctoria)root. Additional clinical studies are needed to make a conclusion.

• Caution is advised when taking echinacea supplements, as numerous adverse effects including drug interactions are possible. Echinacea should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Essiac®: Essiac® contains a combination of herbs, including burdock root (Arctium lappa), sheep sorrel (Rumex acetosella), slippery elm inner bark (Ulmus fulva), and Turkish rhubarb (Rheum palmatum). The original formula was developed by the Canadian nurse Rene Caisse (1888-1978) and is thought to be effective in cancer therapies, although currently there is not enough evidence to recommend for or against the use of this herbal mixture as a therapy for any type of cancer. Different brands may contain variable ingredients, and the comparative effectiveness of these formulas is not known. None of the individual herbs used in Essiac® has been tested in rigorous human cancer trials, although some components have anti-tumor activity in laboratory studies. Numerous individual patient testimonials and reports from manufacturers are available on the Internet, although these cannot be considered scientifically viable as evidence. Individuals with cancer are advised not to delay treatment with more proven therapies. Caution is advised when taking Essiac® supplements, as numerous adverse effects including drug interactions are possible. Essiac® should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Focusing: Focusing (experiential therapy) is a method of psychotherapy that involves being aware of one's feelings surrounding a particular issue and understanding the meaning behind words or images conveyed by those feelings. Early evidence suggests focusing may improve mood and attitude in cancer patients. Firm recommendations cannot be made until well-designed clinical trials are available.

• Side effect reporting is rare, but patients should consult with a qualified healthcare practitioner before making decisions about medical conditions and practices. Individuals with severe emotional difficulties should not abandon proven medical and psychological therapies but rather choose focusing as a possible adjunct.

• Folic acid: Folic acid or folate is a form of a water-soluble B vitamin needed for human health. Preliminary evidence suggests that folate may decrease the risk of several types of cancer. Additional research is needed to make a conclusion. Folic acid supplementation may mask the symptoms of pernicious, aplastic, or normocytic anemias caused by vitamin B12 deficiency and may lead to neurological damage.

• Avoid if allergic or hypersensitive to folate or any folate product ingredients. Use cautiously if receiving coronary stents and with anemia and seizure disorders. It is recommended that pregnant women consume 400 micrograms daily in order to reduce the risk of fetal defects. Folate is likely safe if breastfeeding.

• Gamma linolenic acid (GLA): GLA is an omega-6 essential fatty acid. Some laboratory and human studies indicate that GLA may have anti-tumor activity and may be used as a cancer treatment adjunct. Additional research is needed in this area.

• Caution is advised when taking GLA supplements, as numerous adverse effects including an increased risk of bleeding and drug interactions are possible. GLA should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Garlic: Preliminary human studies suggest that regular consumption of garlic (Allium sativum) supplements may reduce the risk of developing several types of cancer. Some studies use multi-ingredient products so it is difficult to determine if garlic alone may play a beneficial role in cancer prevention. Further well-designed human clinical trials are needed to conclude whether eating garlic or taking garlic supplements may prevent or treat cancer.

• Caution is advised when taking garlic supplements, as numerous adverse effects including an increased risk of bleeding and drug interactions are possible. Garlic should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Ginseng: Early studies report that ginseng taken by mouth may be of benefit in cancer prevention, especially if ginseng powder or extract is used. Weak studies suggest that ginseng in combination with other herbs may improve cell activity, immune function, and red and white blood cell counts in patients with aplastic anemia; however, other studies have found decreases in blood cell counts. Early studies suggest that ginseng may decrease radiation therapy side effects and may be used as a chemotherapy adjunct to improve body weight, quality of life, and the immune response. There is currently not enough evidence to recommend the use of Panax ginseng or American ginseng for these indications. Study results are unclear, and more research is needed before a clear conclusion can be reached.

• Caution is advised when taking ginseng supplements, as numerous adverse effects including an increased risk of drug interactions are possible. Ginseng should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Goji: Polysaccharide constituents, such as alpha- and beta-glucans from a variety of plants, are reported to have immune system enhancing properties. In clinical study, Lycium barbarum polysaccharides (LBP) demonstrated a synergistic effect in various cancer treatments, when administered in conjunction with powerful immune stimulating drugs.

• Use cautiously in patients who are taking blood-thinning medications, such as warfarin. Use cautiously in asthma patients and in patients with sulfite sensitivities. The New York Department of Agriculture has detected the presence of undeclared sulfites, a food additive, in two dried goji berry products from China. Avoid in patients who are allergic to goji, any of its constituents, or to members of the Solanaceae family.

• Grape seed: There is currently little information available on the use of grape seed extract in the treatment of human cancer. Further research is needed before a recommendation can be made.

• Avoid if allergic or hypersensitive to grapes or other grape compounds. Use cautiously with bleeding disorders or if taking blood thinners such as warfarin, aspirin, non-steroidal anti-inflammatory drugs (NSAIDS), or anti-platelet agents. Use cautiously with drugs processed using the liver's cytochrome P450 enzyme system. Use cautiously with blood pressure disorders or if taking ACE inhibitors. Avoid if pregnant or breastfeeding.

• Green tea: Green tea is made from the dried leaves of Camellia sinensis, a perennial evergreen shrub. Green tea has a long history of use in health and longevity, dating back to China approximately 5,000 years ago. Although used for centuries to help prevent diseases, the relationship of green tea consumption and human cancer in general remains inconclusive. Evidence from well-designed clinical trials is needed before a firm conclusion can be made in this area.

• Caution is advised when taking green tea supplements, as numerous adverse effects including an increased risk of drug interactions are possible. Green tea should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Healing touch: Preliminary data suggests that healing touch (HT) may increase quality of life in cancer. However, due to weaknesses in design and the small number of studies, data are insufficient to make definitive recommendations. Studies with stronger designs are needed. HT should not be regarded as a substitute for established medical treatments. Use cautiously if pregnant or breastfeeding.

• Hoxsey formula: "Hoxsey formula" is a misleading name, because it is not a single formula, but rather is a therapeutic regimen consisting of an oral tonic, topical (on the skin) preparations, and supportive therapy. The tonic is individualized for cancer patients based on general condition, location of cancer, and previous history of treatment. An ingredient that usually remains constant for every patient is potassium iodide. Other ingredients are then added and may include licorice, red clover, burdock, stillingia root, berberis root, pokeroot, cascara, Aromatic USP 14, prickly ash bark, and buckthorn bark. A red paste may be used, which tends to be caustic (irritating), and contains antimony trisulfide, zinc chloride, and bloodroot. A topical yellow powder may be used, and contains arsenic sulfide, talc, sulfur, and a "yellow precipitate." A clear solution may also be administered, and contains trichloroacetic acid.

• Well-designed human studies available evaluating the safety or effectiveness of Hoxsey formula are currently lacking. Caution is advised when taking the Hoxsey formula supplements, as numerous adverse effects including an increased risk of drug interactions are possible. Hoxsey formula should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Hydrazine sulfate: Hydrazine is an industrial chemical marketed as having the potential to repress weight loss and cachexia (muscle wasting) associated with cancer, and to improve general appetite status. However, in large randomized controlled trials, hydrazine has not been proven effective for improving appetite, reducing weight loss, or improving survival in adults. The National Cancer Institute (NCI) sponsored studies of hydrazine sulfate that claimed efficacy in improving survival for some patients with advanced cancer. Trial results found that hydrazine sulfate did not prolong survival for cancer patients. The U.S. Food and Drug Administration (FDA) has received requests from individual physicians for approval to use hydrazine sulfate on a case-by-case "compassionate use" basis on the chance that patients with no other available effective cancer treatment options might benefit from this therapy. The overall controversy in the use of hydrazine sulfate is ongoing, and relevance to clinical practice is unknown. The use of hydrazine sulfate needs to be evaluated further before any recommendations can be made.

• Hydrazine sulfate may cause cancer. Avoid if allergic or hypersensitive to hydrazine sulfate or any of its constituents. Use cautiously with liver or kidney problems, psychosis, diabetes or seizure disorders. Avoid if pregnant or breastfeeding. Side effects have been reported, including dizziness, nausea, and vomiting.

• Iodine: Iodine is an element (atomic number 53), which is required by humans for the synthesis of thyroid hormones (triiodothyronine/T3 and thyroxine/T4). The potential role of non-radioactive iodine in cancer care remains unknown. Antioxidant and anti-tumor effects have been proposed based on laboratory research. In contrast, some scientists have asserted that tumors may uptake more iodine than normal tissues. It has been suggested that high rates of gastric (stomach) cancer or low rates of breast cancer in coastal Japan may be due to high iodine intake, although this has not been demonstrated scientifically. Povidone-iodine solutions have been used as a part of alternative cancer regimens, such as the Hoxsey formula. Preliminary study has also indicated povidone-iodone solution as a potential rectal washout for rectal cancer. Overall, no clear conclusion can be drawn based on the currently available evidence.

• Reactions can be severe, and deaths have occurred with exposure to iodine. Avoid iodine-based products if allergic or hypersensitive to iodine. Do no use for more than 14 days. Avoid Lugol solution and saturated solution of potassium iodide (SSKI, PIMA) with hyperkalemia (high amounts of potassium in the blood), pulmonary edema (fluid in the lungs), bronchitis, or tuberculosis. Use cautiously when applying to the skin because it may irritate/burn tissues. Use sodium iodide cautiously with kidney failure. Avoid sodium iodide with gastrointestinal obstruction. Iodine is safe in recommended doses for pregnant or breastfeeding women. Avoid povidone-iodine for perianal preparation during delivery or postpartum antisepsis.

• Jiaogulan: Preliminary evidence indicates that gypenosides extracted from Gynostemma pentaphyllum may decrease cancer cell viability, arrest the cell cycle, and induce apoptosis (cell death) in human cancer cells. Immune function in cancer patients has also been studied. Additional study is needed in this area.

• Avoid if allergic or hypersensitive to jiaogulan (Gynostemma pentaphyllum), its constituents, or members of the Cucurbitaceae family. Use cautiously with blood disorders or taking anticoagulants or anti-platelet drugs (blood thinners). Use cautiously with diabetes. Avoid if pregnant or breastfeeding.

• Lavender: Perillyl alcohol (POH), derived from lavender (Lavendula officinalis), may be beneficial in the treatment of some types of cancer. Preliminary small studies in humans, involving the use of POH suggest safety and tolerability, but effectiveness has not been established.

• Avoid if allergic or hypersensitive to lavender. Avoid with a history of seizures, bleeding disorders, eating disorders (anorexia, bulimia), or anemia (low levels of iron). Avoid if pregnant or breastfeeding.

• Lutein: Currently, there is insufficient available evidence to recommend for or against the use of lutein for cancer. Available evidence in humans is conflicting.

• Avoid if allergic or hypersensitive to lutein or zeaxanthin. Use cautiously if at risk for cardiovascular disease or cancer. Avoid if pregnant or breastfeeding.

• Lycopene: High levels of lycopene are found in tomatoes and in tomato-based products. Tomatoes are also sources of other nutrients such as vitamin C, folate, and potassium. Several laboratory and human studies examining tomato-based products and blood lycopene levels suggest that lycopene may be associated with a lower risk of developing cancer and may help stimulate the immune system. However, due to a lack of well-designed human research using lycopene supplements, its effectiveness for cancer prevention remains unclear.

• Avoid if allergic to tomatoes or to lycopene. Due to a lack of conclusive data, avoid if pregnant or breastfeeding.

• Maitake mushroom: Maitake is the Japanese name for the edible mushroom Grifola frondosa. Maitake has been used traditionally both as a food and for medicinal purposes. Early studies in the laboratory as well as in humans suggest that beta-glucan extracts from maitake may increase the body's ability to fight cancer. However, these studies have not been well designed, and better research is needed before the use of maitake for cancer can be recommended.

• Caution is advised when taking maitake supplements, as numerous adverse effects including an increased risk of bleeding and drug interactions are possible. Maitake should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Meditation: Not enough research has shown meditation to be of benefit in cancer prevention. More studies are needed.

• Use cautiously with underlying mental illnesses. People with psychiatric disorders should consult with their primary mental healthcare professional(s) before starting a program of meditation, and should explore how meditation may or may not fit in with their current treatment plan. Avoid with risk of seizures. The practice of meditation should not delay the time to diagnosis or treatment with more proven techniques or therapies, and should not be used as the sole approach to illnesses.

• Melatonin: There are several early-phase and controlled human trials of melatonin in patients with various advanced stage malignancies. There is currently not enough definitive scientific evidence to discern if melatonin is beneficial as a cancer treatment, whether it increases (or decreases) the effectiveness of other cancer therapies, or if it safely reduces chemotherapy side effects.

• Melatonin is not to be used for extended periods of time. Caution is advised when taking melatonin supplements, as numerous adverse effects including drug interactions are possible. Melatonin is not recommended during pregnancy or breastfeeding unless otherwise advised by a doctor.

• Milk thistle: Milk thistle (Silybum marianum) has been used medicinally in China for over 2,000 years, most commonly for the treatment of liver and gallbladder disorders. There are early reports from laboratory experiments that the components silymarin and silibinin found in milk thistle may reduce the growth of human cancer cells. However, effects have not been shown in high-quality human trials.

• Caution is advised when taking milk thistle supplements, as numerous adverse effects including an increased risk of bleeding and drug interactions are possible. Milk thistle should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Mistletoe: Mistletoe is one of the most widely used unconventional cancer treatments in Europe. Mistletoe extracts have been studied for a variety of human cancers as well as melanoma and leukemia. However, efficacy has not been conclusively proven for any one condition. In fact, some studies have shown lack of efficacy of certain preparations for a variety of cancers. Larger, well-designed clinical trials are needed.

• Caution is advised when taking mistletoe supplements, as numerous adverse effects including nausea, vomiting, and drug interactions are possible. Mistletoe should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Moxibustion: Moxibustion is a healing technique employed across the diverse traditions of acupuncture and oriental medicine for over 2,000 years. Moxibustion uses the principle of heat to stimulate circulation and break up congestion or stagnation of blood and chi. Moxibustion is closely related to acupuncture as it is applied to specific acupuncture points. Preliminary evidence suggests that moxibustion may reduce side effects of chemotherapy or radiation therapy. More studies are needed.

• Use cautiously over large blood vessels and thin or weak skin. Avoid with aneurysms, any kind of "heat syndrome," cardiac disease, convulsions or cramps, diabetic neuropathy, extreme fatigue and/or anemia, fever, inflammatory conditions, over allergic skin conditions or ulcerated sores, or skin adhesions. Avoid if pregnant or breastfeeding. Avoid areas with an inflamed organ, contraindicated acupuncture points, face, genitals, head, inflamed areas in general, nipples, and skin adhesions. Avoid in patients who have just finished exercising or taking a hot bath or shower. Use cautiously with elderly people with large vessels. It is considered not advisable to bathe or shower for up to 24 hours after a moxibustion treatment.

• Oleander: Laboratory studies of oleander (Nerium oleander) suggest possible anti-cancer effects, although reliable research in humans is not currently available. There are reports that long-term use of oleander may have positive effects in patients several types of cancer. More research is needed.

• Caution is advised when taking oleander supplements, as numerous adverse effects including drug interactions are possible. Oleander should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Omega-3 fatty acids: Omega-3 fatty acids are essential fatty acids found in some plants and fish. A balance of omega-6 and omega-3 fatty acids is advised for health. Several population studies report that dietary omega-3 fatty acids or fish oil may reduce the risk of developing several different types of cancer. Well conducted clinical trials are necessary before a clear conclusion can be drawn regarding the use of omega-3 fatty acids for cancer prevention.

• Caution is advised when taking omega-3 fatty acid supplements, as numerous adverse effects including an increase in bleeding and drug interactions are possible. Omega-3 fatty acid supplements should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Para-aminobenzoic acid: N-butyl-p-aminobenzoate (BAB) has been shown to be a lipid-soluble local anesthetic. Early study found significant pain relief in patients with intractable cancer pain after an epidural injection of BAB suspension. Larger scale clinical study is needed to confirm these findings.

• Avoid with known hypersensitivity to PABA or its derivatives. Avoid oral use in children and pregnant or nursing women. Use cautiously in patients with renal disease, bleeding disorders or taking anticoagulants, diabetics or patients at risk for hypoglycemia. Discontinue use if rash, nausea, or anorexia occurs. Pharmaceutical doses of PABA and its derivatives should only be taken under appropriate medical supervision. PABA should not be given concurrently with sulfonamides.

• Perillyl alcohol: Perillyl alcohol has been used to treat cancer. However, high quality scientific studies are lacking. Further research is required before recommendations can be made.

• Avoid if allergic/hypersensitive to perillyl alcohol. Avoid use in the absence of medical supervision. Use cautiously in patients under medical supervision. Avoid if pregnant or breastfeeding.

• Prayer: Initial studies of prayer in patients with cancer (such as leukemia) report variable effects on disease progression or death rates when intercessory prayer is used. Better quality research is necessary before a firm conclusion can be drawn.

• Prayer is not recommended as the sole treatment approach for potentially serious medical conditions, and should not delay the time it takes to consult with a healthcare professional or receive established therapies. Sometimes religious beliefs come into conflict with standard medical approaches, and require an open dialog between patients and caregivers. In clinical study, patients certain that they were receiving intercessory prayer had a higher incidence of complications following cardiac bypass surgery than those who did not know they were being prayed for.

• PSK: PSK, or protein-bound polysaccharide, is obtained from cultured mycelia of Coriolus versicolor, a mushroom thought to have antimicrobial, antiviral, and antitumor properties. Preliminary human study in patients with acute leukemia suggests that adjunct PSK therapy may prolong duration of remission and survival time. In other study in patients with acute nonlymphocytic leukemia, no significant increases in survival were found. Well-designed clinical trials are required in order to determine if PSK therapy may in fact prolong remission and increase survival time in individuals with acute leukemia.

• PSK generally seems to have a low incidence of mild and tolerable side effects. In one report, three cases of toxicity were noted, and PSK was discontinued. PSK has been associated with side effects of gastrointestinal upsetand darkening of the fingernails, but these effects have been limited and general safety has been demonstrated with daily oral doses for extended periods. Darkening of the fingernails and coughing have been reported during administration of the powder form of PSK.

• Reiki: Reiki may contribute to reduced perception of pain, improved quality of life, and reduced fatigue in cancer patients. More studies are needed.

• Reiki is not recommended as the sole treatment approach for potentially serious medical conditions, and should not delay the time it takes to consult with a healthcare professional or receive established therapies. Use cautiously with psychiatric illnesses.

• Reishi mushroom: Reishi (Ganoderma lucidum) has been shown to have antineoplastic and immunomodulatory effects in animal studies. Human studies exist of advanced cancer patients using Ganopoly®, a Ganoderma lucidum polysaccharide extract. Results show improved quality of life and enhanced immune responses, which are typically reduced or damaged in cancer patients receiving chemotherapy and/or radiation therapy. Well-designed long-term studies are needed confirm these results and to determine potential side effects.

• Caution is advised when taking reishi supplements, as numerous adverse effects including an increased risk of bleeding and drug interactions are possible. Reishi should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Resveratrol: The effects of resveratrol cannot be adequately assessed from trials using foods, wine, or combination products containing resveratrol and other substances. Well-designed clinical trials of resveratrol alone are needed before a recommendation can be made in regards to cancer prevention and/or treatment.

• Avoid if allergic or hypersensitive to resveratrol, grapes, red wine or polyphenols. Resveratrol is generally considered safe and is commonly found in food and beverages. Use cautiously with bleeding disorders, abnormal blood pressure. Use cautiously with drugs that are broken down by the body's cytochrome P450 system or digoxin (or digoxin-like drugs). Avoid if pregnant or breastfeeding.

• Seaweed: Bladderwrack (Fucus vesiculosus) is a brown seaweed that grows on the northern coasts of the Atlantic and Pacific oceans, and the North and Baltic seas. Bladderwrack appears to suppress the growth of various cancer cells in animal and laboratory studies. However, reliable human studies to support a recommendation for use in cancer are currently lacking.

• Caution is advised when taking bladderwrack supplements, as numerous adverse effects including an increased risk of drug interactions are possible. Bladderwrack should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Selenium: Selenium is a trace mineral found in soil, water, and some foods. It is an essential element in several metabolic pathways. Several studies suggest that low levels of selenium (measured in the blood or in tissues such as toenail clippings), may be a risk factor for developing cancer. Population studies suggest that people with cancer are more likely to have low selenium levels than healthy matched individuals, but in most cases it is not clear if the low selenium levels are a cause or merely a consequence of disease. It currently remains unclear if selenium is beneficial for cancer prevention or cancer treatment.

• Avoid if allergic or sensitive to products containing selenium. Avoid with a history of nonmelanoma skin cancer. Selenium is generally regarded as safe for pregnant or breastfeeding women. However, animal research reports that large doses of selenium may lead to birth defects.

• Shark cartilage: For several decades, shark cartilage has been proposed as a cancer treatment. Studies have shown shark cartilage or the shark cartilage product AE-941 (Neovastat®) to block the growth of new blood vessels, a process called "anti-angiogenesis," which is believed to play a role in controlling growth of some tumors. There have also been several reports of successful treatments of end-stage cancer patients with shark cartilage, but these have not been well-designed and have not included reliable comparisons to accepted treatments. Many studies have been supported by shark cartilage product manufacturers, which may influence the results. In the United States, shark cartilage products cannot claim to cure cancer, and the U.S. Food and Drug Administration (FDA) has sent warning letters to companies not to promote products in this way. Without further evidence from well-designed human trials, it remains unclear if shark cartilage is of any benefit in cancer and patients are advised to check with their doctor and pharmacist before taking shark cartilage.

• Shark cartilage available in Asian grocery stores and restaurants should not be eaten due to declining populations of sharks. Caution is advised when taking shark cartilage supplements, as numerous adverse effects including an increased risk of drug interactions are possible. Shark cartilage should not be used by patients who are pregnant or breast-feeding, unless otherwise directed by a doctor.

• Shiitake mushroom: Shiitake (Lentinus edodes) has been taken by mouth for boosting the immune system, decreasing cholesterol levels, and for anti-aging. Lentinan, derived from shiitake, has been injected as an adjunct treatment for cancer and HIV infection. Laboratory, animal and human studies of lentinan have shown positive results in cancer patients when used as a chemotherapy adjunct. Further well-designed clinical trials on all types of cancer are required to confirm these results.

• Caution is advised when taking shiitake supplements, as numerous adverse effects including an increased risk of bleeding and drug interactions are possible. Shiitake should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Slippery elm: Slippery elm is found as a common ingredient in a purported herbal anticancer product called Essiac® and a number of Essiac-like products. These products contain other herbs such as rhubarb, sorrel, and burdock root. Currently, there is not enough evidence to recommend for or against the use of this herbal mixture as a therapy for any type of cancer. Avoid if allergic or hypersensitive to slippery elm. Avoid if pregnant or breastfeeding.

• Sorrel: Early evidence suggests that herbal formulations containing sorrel, such as Essiac®, do not shrink tumor size or increase life expectancy in patients with cancer. However, currently there is a lack of studies evaluating sorrel as the sole treatment for cancer. A conclusion cannot be made without further research.

• Avoid with a known allergy or hypersensitivity to sorrel. Avoid large doses due to reports of toxicity and death, possibly because of the oxalate found in sorrel. Many tinctures contain high levels of alcohol and should be avoided when driving or operating heavy machinery. Sorrel formulations may cause nausea or vomiting when taken with the prescription drugs metronidazole (Flagyl®) or disulfiram (Antabuse®). Avoid if pregnant or breastfeeding.

• Soy: Soy (Glycine max) contains compounds which have been reported to be effective as a cancer treatment. Genistein, an isoflavone found in soy, has been found in laboratory and animal studies to possess anti-cancer effects, such as blocking new blood vessel growth (anti-angiogenesis), acting as a tyrosine kinase inhibitor (a mechanism of many new cancer treatments), or causing cancer cell death (apoptosis). In contrast, genistein has also been reported to increase the growth of pancreas tumor cells in laboratory research. Until reliable human research is available, it remains unclear if dietary soy or soy isoflavone supplements are beneficial, harmful, or neutral in people with various types of cancer.

• Caution is advised when taking soy supplements, as numerous adverse effects including an increased risk of drug interactions are possible. Soy should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Spiritual healing: Cancer patients, especially those who fear recurrence or are unhappy with their physicians, commonly use prayer and spiritual healing. More research is needed to address the effects of spiritual healing on anxiety, depression, and quality of life in patients with cancer.

• Spiritual healing should not be used as the only treatment approach for medical or psychiatric conditions, and should not delay the time it takes to consider more proven therapies.

• Sweet annie: Certain constituents found in sweet annie show promise for use in cancer when used in combination with standard chemotherapy. However, currently there is not enough scientific evidence in humans to make a strong recommendation for this use.

• Avoid if allergic or hypersensitive to sweet annie (Artemisia annua), its constituents, or members of the Asteraceae/Compositae family such dandelion, goldenrod, ragweed, sunflower, and daisies. Use cautiously in patients who are pregnant, taking angiogenic agents, or recovering from surgery or other wounds. Use cautiously if taking cardiotoxic or neurotoxic agents or with compromised cardiac or neural function. Use cautiously if taking immunostimulants or quinolines. Avoid if pregnant or breastfeeding.

• Transcutaneous electrical nerve stimulation (TENS): Transcutaneous electrical nerve stimulation (TENS) is a non-invasive technique in which a low-voltage electrical current is delivered through wires from a small power unit to electrodes located on the skin. Although TENS has been used with some success in cancer pain, there is not enough reliable evidence to draw a firm conclusion in this area. TENS is often used in combination with acupuncture.

• Avoid with implantable devices, like defibrillators, pacemakers, intravenous infusion pumps, or hepatic artery infusion pumps. Use cautiously with decreased sensation, like neuropathy, and with seizure disorders. Avoid if pregnant or breastfeeding.

• Thiamin (Vitamin B1): Thiamin deficiency has been observed in some cancer patients, possibly due to increased metabolic needs. It is not clear if lowered levels of thiamin in such patients may actually be beneficial. Currently, it remains unclear if thiamin supplementation plays a role in the management of any particular type(s) of cancer.

• Thiamin is generally considered safe and relatively nontoxic. Avoid if allergic or hypersensitive to thiamin. Rare hypersensitivity/allergic reactions have occurred with thiamin supplementation. Skin irritation, burning, or itching may rarely occur at injection sites. Large doses may cause drowsiness or muscle relaxation. Use cautiously if pregnant or breastfeeding.

• Thymus extract: Preliminary evidence suggests that thymus extract may increase disease-free survival and immunological improvement in several types of cancer. Additional study is needed in this area.

• Avoid if allergic or hypersensitive to thymus extracts. Use bovine thymus extract supplements cautiously due to potential for exposure to the virus that causes "mad cow disease." Avoid with an organ transplant or other forms of allografts or xenografts. Avoid if receiving immunosuppressive therapy, with thymic tumors, myasthenia gravis (neuromuscular disorder), untreated hypothyroidism, or if taking hormonal therapy. Avoid if pregnant or breastfeeding.

• Traditional Chinese Medicine (TCM): The ancient Chinese philosophy of Taoism provided the basis for the development of Chinese medical theory. TCM uses over 120 different herbs in cancer treatment, depending on the type of cancer and its cause according to Chinese medical theory. Studies have reported significant benefits include reducing tumors, reducing treatment side effects and improved response to treatment. More studies of stronger design are needed before TCM can be recommended with confidence as an adjunct to cancer treatment, although centuries of traditional use in cancer cannot be discounted.

• Chinese herbs can be potent and may interact with other herbs, foods or drugs. Consult a qualified healthcare professional before taking. There have been reports of manufactured or processed Chinese herbal products being tainted with toxins or heavy metal or not containing the listed ingredients. Herbal products should be purchased from reliable sources. Avoid ma huang, which is the active ingredient in ephedra. Avoid ginseng if pregnant or breastfeeding.

• Turmeric: Turmeric (Curcuma longa) is commonly used for its anti-inflammatory properties. Several early animal and laboratory studies report anti-cancer (colon, skin, breast) properties of curcumin. Many mechanisms have been considered, including antioxidant activity, anti-angiogenesis (prevention of new blood vessel growth), and direct effects on cancer cells. Currently it remains unclear if turmeric or curcumin has a role in preventing or treating human cancer. There are several ongoing studies in this area.

• Caution is advised when taking turmeric supplements, as numerous adverse effects including an increased risk of bleeding and drug interactions are possible. Turmeric should not be used if pregnant or breast-feeding, unless otherwise directed by a doctor.

• Vitamin C (ascorbic acid): Dietary intake of fruits and vegetables high in vitamin C has been associated with a reduced risk of various types of cancer in population studies (particularly cancers of the mouth, esophagus, stomach, colon, or lung). However, it is not clear that it is specifically the vitamin C in these foods that is beneficial, and vitamin C supplements have not been found to be associated with this protective effect. Experts have recommended increasing dietary consumption of fruits and vegetables high in vitamin C, such as apples, asparagus, berries, broccoli, cabbage, melon (cantaloupe, honeydew, watermelon), cauliflower, citrus fruits (lemons, oranges), fortified breads/grains/cereal, kale, kiwi, potatoes, spinach, and tomatoes. Vitamin C has a long history of adjunctive use in cancer therapy, and although there have not been any definitive studies using intravenous (or oral) vitamin C, there is evidence that it has benefit in some cases. Better-designed studies are needed to better determine the role of vitamin C in cancer prevention and cancer treatment.

• Avoid if allergic or sensitive to vitamin C product ingredients. Vitamin C is generally considered safe in amounts found in foods. Vitamin C supplements are also generally considered safe in most individuals if taken in recommended doses. Large doses (greater than 2 grams) may cause diarrhea and gastrointestinal upset. Avoid high doses of vitamin C with glucose 6-phosphate dehydrogenase deficiency, kidney disorders or stones, cirrhosis (inflammation of the liver), gout, or paroxysmal nocturnal hemoglobinuria (bleeding disorder). Vitamin C intake from food is generally considered safe if pregnant or breastfeeding. It is not clear if vitamin C supplements in doses higher than Dietary Reference Intake recommendations are safe for pregnant or breastfeeding women. Vitamin C is naturally found in breast milk.

• Vitamin D: Limited research suggests that synthetic vitamin D analogs may play a role in the treatment of human cancers. However, it remains unclear if vitamin D deficiency raises cancer risk, or if an increased intake of vitamin D is protective against some cancers. Until additional trials are conducted, it is premature to advise the use of regular vitamin D supplementation for cancer prevention.

• Avoid if allergic or hypersensitive to vitamin D or any of its components. Vitamin D is generally well-tolerated in recommended doses; doses higher than recommended may cause toxic effects. Use cautiously with hyperparathyroidism (overactive thyroid), kidney disease, sarcoidosis, tuberculosis, and histoplasmosis. Vitamin D is safe in pregnant and breastfeeding women when taken in recommended doses.

• Vitamin E: Reliable scientific evidence that vitamin E is effective as a cancer treatment is currently lacking.

• Caution is merited in people undergoing chemotherapy or radiation, because it has been proposed that the use of high-dose antioxidants may actually reduce the anti-cancer effects of these therapies. This remains an area of controversy and studies have produced variable results. Patients interested in using high-dose antioxidants such as vitamin E during chemotherapy or radiation should discuss this decision with their medical oncologist or radiation oncologist. Caution is advised when taking vitamin E supplements, as numerous adverse effects including an increased risk of bleeding and drug interactions are possible. Avoid if allergic or hypersensitive to vitamin E. Avoid with retinitis pigmentosa (loss of peripheral vision). Use cautiously with bleeding disorders or if taking blood thinners. Avoid above the recommended daily level in pregnant women and breastfeeding women.

• Fair negative scientific evidence:

• Apricot: Available clinical trials on the use of whole apricots for cancer are currently lacking. However, some research has been conducted on "Laetrile™," an alternative cancer drug marketed in Mexico and other countries outside of the U.S. Laetrile™ is derived from amygdalin found in apricot pits and nuts such as bitter almond. There are multiple animal studies and initial human evidence to suggest that Laetrile™ is not beneficial in the treatment of cancer. Based on a phase II trial in 1982, the U.S. National Cancer Institute concluded that Laetrile™ is not an effective chemotherapeutic agent. Nonetheless, many people still travel to use this therapy outside the U.S.

• Multiple cases of cyanide poisoning, including deaths, have been associated with Laetrile™ therapy. Avoid if allergic to apricot, its constituents or members of the Rosaceae family, especially the Prunoideae subfamily of plants. Avoid eating excessive amounts of apricot kernels (about 7 grams daily, or more than ten kernels daily). Use cautiously with diabetes. Use cautiously when taking supplements containing beta-carotene, iron, niacin, potassium, thiamine or vitamin C. Use cautiously when taking products that may lower blood pressure. Avoid if pregnant or breastfeeding.

• Beta-carotene: While diets high in fruits and vegetables rich in beta-carotene have been shown to potentially reduce certain cancer incidences, results from randomized controlled trials with oral supplements do not support this claim.

• There is some concern that beta-carotene metabolites with pharmacological activity can accumulate and potentially have cancer-causing (carcinogenic) effects. A higher, statistically significant incidence of lung cancer in male smokers who took beta-carotene supplements has been discovered. Beta-carotene/vitamin A supplements may have an adverse effect on the incidence of lung cancer and on the risk of death in smokers and asbestos exposed people or in those who ingest significant amounts of alcohol. In addition, high-dose antioxidants theoretically may interfere with the activity of some chemotherapy drugs or radiation therapy. Therefore, individuals undergoing cancer treatment should speak with their oncologist if they are taking or considering the use of high dose antioxidants. Beta-carotene in the amounts normally found in food does not appear to have this adverse effect. Avoid if sensitive to beta-carotene, vitamin A or any other ingredients in beta-carotene products.

• Bitter almond: "Laetrile" is an alternative cancer drug marketed in Mexico and other countries outside of the United States. Laetrile is derived from amygdalin, found in the pits of fruits and nuts such as the bitter almond. Early evidence suggests that laetrile is not beneficial in the treatment of cancer. In 1982, the U.S. National Cancer Institute concluded that laetrile was not effective for cancer therapy. Nonetheless, many people still travel to use this therapy outside the United States.

• Multiple cases of cyanide poisoning, including deaths, have been associated with laetrile therapy. Avoid if allergic to almonds or other nuts. Use cautiously if driving or operating machinery. Avoid if pregnant or breastfeeding because of the risk of birth defects.

• Hypnotherapy, hypnosis: Hypnosis did not reduce radiotherapy side effects such as anxiety and did not improve quality of life in patients undergoing curative radiotherapy in early high-quality studies.

• Use cautiously with mental illnesses like psychosis/schizophrenia, manic depression, multiple personality disorder or dissociative disorders, or with seizure disorders.

• Iridology: There is currently limited available data supporting iridology as a tool for cancer diagnosis. Additional study is needed.

• Iridology should not be used alone to diagnose disease. Studies of iridology have reported incorrect diagnoses, and thus, potentially severe medical problems may go undiagnosed. In addition, research suggests that iridology may lead to inappropriate treatment. Iridology is therefore not recommended as a sole method of diagnosis or treatment for any condition.

• Vitamin E: Recent evidence from well-conducted clinical study reports no reduction in the development of cancer with the use of natural-source vitamin E taken daily. Previously, there have been laboratory, population, and other human trials examining whether vitamin E is beneficial in general cancer prevention, including that for prostate, colon, or stomach cancer. Results of these prior studies have been variable. At this time, based on the best available scientific evidence, and recent concerns about the safety of vitamin E supplementation, vitamin E cannot be recommended for cancer prevention.

• Avoid if allergic or hypersensitive to vitamin E. Avoid with retinitis pigmentosa (loss of peripheral vision). Use cautiously with bleeding disorders or if taking blood thinners. Avoid above the recommended daily level in pregnant women and breastfeeding women.

Prevention

• Chemical exposure avoidance: If the individual works with chemicals on a daily basis, such as in the case of hairdressers, printers, and painters, they should follow all safety instructions to avoid unsafe exposure. If an individual has their own well as their water source, they may wish to have it tested for contaminants such as lead and arsenic, which both may be linked to cancer. Local health departments can be a source of water testing.

• Exercise and weight control: Controlling weight and exercising regularly can reduce the risk of developing cancer. The American Cancer Society recommends at least 30 minutes of physical activity five or more days a week if the individual can physically tolerate it.

• Fruits, vegetables and whole grains: Fruits, vegetables and whole grains contain vitamins, minerals, fiber and antioxidants, which may help protect from developing various types of cancer. Eating five or more servings of fresh fruits and vegetables every day is important for good health. A variety of produce should be included in the individual's diet such as kale, chard, spinach, dark green lettuce, peppers, and squashes.

• Limit alcohol consumption: Consuming moderate to heavy amounts of alcohol, such as more than one drink a day for women and two for men, may increase the risk of developing certain cancers. This is particularly true if the individual has a close relative, such as a parent, child or sibling with cancer.

• Smoking cessation: Smoking can increase the risk of cancers such as lung and bladder.

• Vitamins and minerals: Calcium, magnesium, pyridoxine (vitamin B6), and folic acid may help reduce the risk of certain cancers. Good food sources of calcium include skim or low-fat milk and other dairy products, shrimp, and soy products such as tofu and soy milk. Magnesium is found in leafy greens, nuts, peas and beans. Food sources of vitamin B6 include grains, legumes, peas, spinach, carrots, potatoes, dairy foods and meat. Folic acid is found in dark leafy greens such as spinach and lettuce, and in legumes, melons, bananas, broccoli and orange juice.

Bibliography

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

1. American Academy of Family Physicians. http://familydoctor.org.

2. American Cancer Society. www.cancer.org.

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4. Centers for Disease Control and Prevention (CDC). www.cdc.gov.

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7. Leukemia and Lymphoma Society. www.leukemia-lymphoma.org.

8. Lightfoot TJ, Roman E. Causes of childhood leukaemia and lymphoma. Toxicol Appl Pharmacol. 2004 Sep 1;199(2):104-17. View Abstract

9. National Cancer Institute. www.cancer.gov.

10. Natural Standard: The Authority on Integrative Medicine. www.naturalstandard.com.

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12. Robak T. Recent progress in the management of chronic lymphocytic leukemia. Cancer Treat Rev. 2007 Sep 26; [Epub ahead of print]. View Abstract