What is external beam radiation therapy?

Radiation therapy works well to keep cancer from coming back in early-stage breast cancer.

Many people with early breast cancers are treated with radiation 5 days a week for about 3 weeks. This treatment schedule is called "hypofractionated." Some people are treated for a longer period of time. Talk with your doctor about which schedule is right for you. It will depend on:

• The type of breast cancer you have.
• Any other health problems.
• Your preference.

External beam radiation therapy uses doses of radiation to kill cancer cells. A beam of radiation is aimed at the tumor from outside the body. This treatment is given to most people with early-stage breast cancer who choose breast-conserving surgery such as lumpectomy.

• You may need to put on a hospital gown or robe. Wear clothing that is comfortable and easy to take off and put on again later.
• The radiation therapist will mark the treatment spot with tattoos or tiny dots of ink. The radiation must focus on the same area every time. If the dots seem to fade between treatments, tell your radiation therapist.
• You may have shields, or blocks, between the machine and other parts of your body. The shields protect those parts of your body from radiation.
• You'll be asked not to move during treatment. If you're having radiation treatment to the head, you may wear a special mask over your face to keep your head still. Other types of braces or casts may be used to help you be in the exact same position for each treatment. If you keep still, then the radiation goes only where it is needed. You can breathe normally.
• Expect the radiation machine to make noises, such as humming and clicking. The sound may worry you, but the machine is under the therapist's control. The machine is checked often to make sure it works as it should. If you are nervous, tell the radiation therapist. Ask any questions you have.
• Talk to your doctor about what activities you can do before, during, and after treatments.

Radiation therapy is used to destroy any trace of cancer cells that might remain in the body after surgery. It is given to most people with early-stage breast cancer who choose breast-conserving surgery such as lumpectomy. It may also be given after a mastectomy if there's a high risk of the cancer coming back.