Primary Bone Cancer: Radiation Therapy
What is radiation therapy?
Radiation therapy uses high-energy radiation from X-rays or particles to kill cancer cells.
When radiation therapy is used
Radiation therapy can be part of the treatment for some types of primary bone cancers (cancers that start in the bones). For example, it is often part of the treatment for Ewing sarcomas, but it is not used as often for other bone cancers. There are several reasons your healthcare provider may recommend this therapy:
To try to shrink a tumor before surgery. This may make it easier to remove the tumor. It also might reduce the amount of surgery needed. When radiation is used before surgery, it’s called a neoadjuvant therapy.
To try to kill any cancer cells left after surgery. When radiation is used after surgery, it’s called an adjuvant therapy. This may be used if your doctor is not sure all the cancer cells were removed.
To ease symptoms caused by tumors that can't be treated with surgery or that have spread to other organs.
For most bone cancers, radiation therapy is not the main treatment. Surgery is generally the main treatment. But some cancers can’t be removed with surgery. And some people are not healthy enough to have surgery.
To plan your whole treatment strategy, consult with a team of cancer specialists. This might include a surgeon, radiation oncologist, and medical oncologist.
What happens during radiation therapy
The most common way to receive radiation for bone cancer is from a machine outside your body that sends out an invisible X-ray beam. This is called external beam radiation therapy (EBRT).
Sometimes special types of EBRT are used to try to limit the doses of radiation reaching nearby normal cells:
Intensity-modulated radiation therapy (IMRT). IMRT uses a computer to control both the direction and the strength (intensity) of the radiation. This also can lessen the side effects on healthy tissue.
Proton beam therapy. This newer type of treatment uses protons instead of X-rays. Protons do less damage to normal, healthy cells as they pass through them, which might lead to fewer side effects.
A doctor who specializes in cancer and radiation is called a radiation oncologist. This doctor works with you to determine the kind of radiation you need. This doctor also determines the dose and how long you need the therapy.
You can usually receive radiation therapy as an outpatient in a hospital or a clinic. This means you will be able to go home the same day. Radiation is often given once a day, 5 days a week, for several weeks.
Getting ready for EBRT
Before your first radiation treatment, you will have a session to plan for the treatment. This is called simulation. During this appointment:
You may have imaging tests, such as CT scans or MRI scans, to help locate the cancer.
You’ll lie still on a table while a radiation therapist uses a machine to find exactly where the radiation will be aimed. The therapist may mark your skin with tiny dots of semi-permanent ink. These are used to aim the radiation at the exact same place each time.
You may have a plastic mold made of your body. The mold helps keep you from moving during the treatment.
What to expect for your treatment
On the days you get radiation treatment, you’ll lie on a table while the machine is placed over you. Each treatment is much like getting an X-ray, only longer.
On the day of treatment, you are carefully put into the right position. You may see lights from the machine lined up with the marks on your skin. These help the therapist know you are in the right position. The therapist will leave the room while the machine sends radiation to your tumor.
During this time, he or she can see you, hear you, and talk to you. When the machine sends radiation to your tumor, you will need to be very still, but you do not have to hold your breath.
Side effects of EBRT
Radiation therapy affects normal cells, as well as cancer cells. This can cause side effects. The side effects from radiation are usually limited to the area being treated. Some people have few or no side effects. But if you do have them, your doctor may change the dose of your radiation or the frequency of treatment. Or the doctor may stop treatment until the side effects are cleared up. Be sure to tell your doctor about any symptoms you have.
Possible short-term side effects
These are some of the common short-term side effects:
Skin irritation or changes in areas that get radiation
Nausea or diarrhea (for radiation to the abdomen or pelvis)
Bladder irritation, which can make you feel that you have to urinate often. Or it may cause pain or burning when you urinate (for radiation to the pelvis).
Extreme tiredness (fatigue)
Low blood counts, as noted on a blood test
If you have any of these side effects, talk with your doctor or nurse. Find out how to deal with them and how to know when they become serious. Often these side effects go away a few weeks after you stop getting treatment.
Possible long-term side effects
Radiation therapy can cause some long-term side effects, depending on where the radiation was aimed. This can be a special concern in treating bone cancer, which often affects children, teens, or young adults. These long-term side effects may include:
Slowed bone growth. Radiation can slow bone growth in children, which may cause one leg to be shorter than the other, for example. This is not as much of a concern in older teens or adults, whose bones are no longer growing.
Second cancers. Cancers are more likely to form in areas that have received radiation. These cancers may develop even decades after treatment.
Reduced fertility. Radiation to the pelvis can damage reproductive organs. This could affect fertility later in life.
Damage to other organs. Organs such as the heart or lungs might be affected by radiation to the chest.
March 21, 2017
Herold, David M., MD,Alteri, Rick, MD