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 But medical information is always changing, and some information given here may be out of date.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

Side Effects of Radiation Therapy


Am Fam Physician. 2010 Aug 15;82(4):394.

  See related article on radiation therapy

What is radiation therapy?

Radiation therapy is a treatment for cancer. It is done by a machine that makes high-energy waves that destroy cancer cells. Radiation therapy is often used for cancers of the skin, head and neck, breast, prostate, cervix, and colon. It can be used to shrink the cancer before you have surgery to remove it. Radiation therapy can also be used with chemotherapy, which is medicine given through an IV.

Are there side effects?

Radiation destroys the cancer cells, but it can also harm healthy cells. Your doctor will plan your treatments to lessen the damage to healthy cells, but there may still be side effects. Before treatment, your radiation oncologist (cancer doctor) and family doctor will review possible side effects and how to prevent or treat them.

What are some side effects and how are they treated?

It depends on the location of the cancer and the amount of radiation you need. Most side effects last only a short time and will go away after the treatments are done. Some side effects can last for a time after your treatments are done.

Some possible side effects and their treatments include:

  • Depression and fatigue. Get at least eight hours of sleep per night and plenty of exercise. Prescription medicines may help.

  • Dry and irritated skin. Use mild, unscented soaps or prescription creams.

  • Nausea and vomiting. Avoid spicy foods and limit alcohol and caffeine. Smaller, more frequent meals may prevent nausea. Prescription medicines may help.

  • Problems with sexual function. Ask your doctor if you can have sex, and discuss your birth control method. Medicines may improve erectile dysfunction and vaginal dryness. Counseling may help you and your partner.

  • Painful urination. Drink plenty of water. Prescription medicines may lessen the pain.

  • Diarrhea. Drink one cup of water for each loose stool.

  • Dry and painful mouth. Lozenges and mouth rinses can help increase your saliva. Medicines to numb the mouth may also help.

Where can I get more information?

AAFP Patient Education Resource

Web site:

American Cancer Society

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 © 2010 by the American Academy of Family Physicians.
This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP. Contact for copyright questions and/or permission requests.

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