Please note: This information was current at the time of publication. But medical information is always changing, and some information given here may be out of date. For regularly updated information on a variety of health topics, please visit, the AAFP patient education website.

Information from Your Family Doctor

Radiation Therapy: What You Should Know


Am Fam Physician. 2008 Dec 1;78(11):1263-1264.

  See related article on radiation therapy.

What is radiation therapy?

Radiation therapy treats cancer by killing cancer cells. It can shrink cancer tumors and stop them from growing or spreading. It can also treat symptoms of cancer, such as pain or bleeding.

How is it given?

Radiation therapy may be given alone or with other treatments, like chemotherapy or surgery. A specialist called a radiation oncologist will discuss your treatment options with you.

Radiation therapy can be external (given through a beam on the outside of your body) or internal (placed inside your body). Radiation can be given as a one-time treatment or in smaller doses given during several treatment sessions. If you have external radiation, you may not need to stay in the hospital. If you have internal radiation, you may be hospitalized for several days. Your doctor can help you decide which type of therapy is best for you.

Are there side effects?

You may feel tired and see changes to the skin in the treated area. Other side effects depend on where your cancer is located. For example, if your cancer is in your mouth or neck, you may have dryness or pain in your throat. If your cancer is in your stomach or abdomen, you may have temporary nausea, vomiting, or diarrhea. If your cancer is in your brain, you may have hair loss.

Most side effects go away within two months of finishing treatment. But some effects may not appear until six months after treatment. These late side effects depend on the part of the body that was treated and on the dose of radiation that was used. They include breathing problems, inability to have children (infertility), and joint problems. Your doctor can prescribe medicine to help with most side effects.

How should I prepare for it?

Your doctor and nurse will meet with you often during your radiation treatment. They will suggest ways that you can prevent some side effects, like not smoking, seeing a dentist and brushing your teeth regularly, drinking plenty of liquids, and getting enough rest. It is also important to tell them if you are having any new symptoms because these may be side effects from treatment.

Where can I get more information?

Your doctor

American Academy of Family Physicians

Web site:

American Cancer Society

Web site:

American Society for Therapeutic Radiology and Oncology

Web sites: and

National Cancer Institute

Web site:

This handout is provided to you by your family doctor and the American Academy of Family Physicians. Other health-related information is available from the AAFP online at

This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.


Copyright © 2008 by the American Academy of Family Physicians.
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