Thyroid Cancer: Frequently Asked Questions
What is the thyroid?
The thyroid gland is located in the front part of the neck, in front of the trachea (windpipe) and esophagus (food-pipe).
Normally, it cannot be seen and usually cannot be felt. It has 2 lobes, the left and the right lobe. These lobes are connected by a bridge of tissue, called the isthmus, to form a dumbbell or butterfly-shaped organ. The thyroid gland takes up iodine from the food we eat. It also makes several important hormones, called thyroid hormones. Thyroid hormones help regulate the body's metabolism, or how the body creates and uses energy. The thyroid gland contains 2 main types of cells. Cells called thyroid follicle cells make and store the thyroid hormone. Cells called C-cells make a hormone called calcitonin. This hormone helps control the calcium levels in the body.
What are the parathyroid glands?
There are 4 small parathyroid glands usually attached at the back of the thyroid gland. They make a hormone called parathyroid hormone. Parathyroid hormone, along with the hormone calcitonin, controls the levels of calcium in the blood.
Who usually gets thyroid cancer?
Women get thyroid cancer more often than men do. Thyroid cancer is often found at a younger age than most other adult cancers. In fact, nearly 2 our of 3 thyroid cancers are found in people younger than age 55. Very few thyroid cancers occur in children and teens.
If I have thyroid nodules does that mean I have thyroid cancer?
Most thyroid nodules (or lumps) are not cancerous. They are sometimes found as lumps on the neck. People can get thyroid nodules at any age, but older adults get them more often. A person may have a multinodular goiter, which means that the thyroid has several nodules. These nodules are sometimes cysts with fluid in them. There can also be extra lumps filled with thyroid hormone, which are called colloid nodules. These are not cancer. Without a biopsy and other tests, however, it is very hard to tell what a thyroid nodule is made of and whether it is cancer or not.
What are the different types of thyroid cancer?
Papillary carcinoma. This is the most common kind of thyroid cancer. It occurs in about 80% of people with thyroid cancer. It is sometimes called papillary cancer or papillary adenocarcinoma.
Follicular carcinoma. This is the second most common type of thyroid cancer. It occurs in 10% of people with thyroid cancer. It is sometimes called follicular cancer, follicular carcinoma, or follicular adenocarcinoma. This kind of cancer usually starts in the thyroid follicle cells.
Medullary thyroid. This cancer occurs in less than 5% of people with thyroid cancer. It is a cancer of the parafollicular or C-cells (named after their production of calcitonin). It can occur sporadically or, in some cases, there is a genetic link, which is called familial medullary thyroid cancer. A blood test can be done to see whether someone carries the gene. If the test shows the gene, family members of the patient should also be tested. This is so that cancer can be prevented or found at an earlier stage in those with the genes.
Anaplastic carcinoma. This occurs in about 2% of people with thyroid cancer. It is also called undifferentiated because the immature cells do not look like the thyroid cells. This type of cancer grows quickly and can be harder to treat than the other types of thyroid cancer.
What are the symptoms of thyroid cancer?
Some of the symptoms of thyroid cancer include: a lump over the thyroid or elsewhere in the neck, neck pain, neck swelling, hoarseness, trouble swallowing, trouble breathing, and a cough that lasts for a long time and is not related to a cold. These symptoms can be caused by many other things besides thyroid cancer. It is important to be checked by a doctor if you have any of these symptoms.
How is the thyroid scan done?
In a thyroid scan, the person will either swallow or be injected with a very small amount of radioactive iodine. A special camera will measure how much iodine is taken up by the thyroid. The scan may show areas within the thyroid without iodine uptake. These are called cold spots and can represent cancer. A biopsy of these is needed because many cold areas are not cancerous. Whole body scans are most helpful after a diagnosis of cancer is made, and can help tell doctors if the cancer has spread to places outside the thyroid gland. Blood tests, including the thyroglobulin test, are also usually done.
How is thyroid cancer treated?
Thyroid cancer may be treated with surgery, radioactive iodine therapy, radiation therapy, chemotherapy, or a combination of these.
The goal of surgery is to remove the tumor from the thyroid, while leaving as much of the thyroid as possible intact. Sometimes the entire thyroid may have to be removed. If this happens, patients will need to take thyroid hormone pills for the rest of their lives, to replace their own missing thyroid hormone.
The goal of radioactive iodine therapy (RAI) is to kill cancer cells using radioactive iodine. RAI is a special form of radiation using iodine. The thyroid cells are uniquely hungry for iodine and pick it up from the blood after injection. This leads to high doses within both the normal and cancerous thyroid, which will kill these cells. Other cells in the body, which do not take up iodine do not get radiation and avoid destruction. If needed, radioiodine treatments can be repeated more than once, to make sure all cancer cells are destroyed. (The same radioactive iodine is used to do a thyroid scan, but much larger doses are used for this treatment.)
The goal of radiation therapy is to kill cancer cells using X-rays. This treatment is used to shrink a tumor before surgery or to get rid of any remaining cancer cells after surgery. Sometimes it is used to treat cancers that cannot be surgically removed.
Chemotherapy is rarely used to treat thyroid cancer. Chemotherapy may be given along with radiation to treat anaplastic thyroid cancer. In thyroid cancer, chemotherapy is less effective than radioactive iodine therapy and usually used when the cancer has spread or has not responded to the radioiodine treatment.
What are clinical trials?
Clinical trials are studies of new kinds of cancer treatments. Doctors conduct clinical trials to learn about how well new treatments work and what their side effects are. If they look promising, they are then compared with the current treatment to see if they work better or have fewer side effects. People who participate in these studies may benefit from access to new treatments before the FDA approves them. Participants also help further our understanding of cancer and help future cancer patients. Clinical trials studying the effectiveness of multikinase inhibitors have recently shown promise for treatment of thyroid and other cancers which have been resistant to other therapies
Should everyone get a second opinion?
Many people with cancer get a second opinion from another doctor. There are many reasons to get a second opinion, including if the person is not comfortable with the treatment decision, if the type of cancer is rare, if there are different ways to treat the cancer, or if the person is not able to see a cancer expert.
How can I get a second opinion?
There are many ways to get a second opinion:
Ask a primary care doctor. He or she may be able to recommend a specialist, such as a surgeon, medical oncologist, or radiation oncologist. Sometimes these doctors work together at cancer centers or programs.
Call the National Cancer Institute's Cancer Information Service. The number is 800-4-CANCER (800-422-6237). They have information about treatment facilities, including cancer centers and other programs supported by the National Cancer Institute.
Seek other options. Patients can get names of doctors from their local medical society, a nearby hospital, a medical school, or local cancer advocacy groups, as well as from other people who have had the same type of cancer.
March 21, 2017
Bible, KC., Position Statement from the International THyroid Oncology Group, the Journal of Clinical Endocrinology and Metabolism (2015); 100/12, 12, pp. 4387-4395
Hurd, Robert, MD,Stump-Sutliff, Kim, RN, MSN, AOCNS