Treatment Overview

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.

How long the treatment takes

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.

Why It Is Done

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.

How Well It Works

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

Risks

External beam radiation works well to destroy cancer cells, but it can also harm normal cells. This can lead to side effects.

The most common short-term side effects of radiation therapy for breast cancer are:

• Feeling very tired (fatigue).
• Skin changes in the treated area. The skin may be red, dry, and sore. Toward the end of treatment, the skin may become moist and "weepy."
• Swelling in the treated breast.

Most short-term side effects will go away within a few weeks after you finish treatment. But it may take longer to get your energy back.

Some side effects may occur months or years after radiation therapy. These long-term side effects may include:

• Changes in skin texture where you had radiation.
• Numbness in your arm from nerve damage.
• Swelling in the arm (lymphedema) if lymph nodes in the armpit were treated.
• In rare cases, heart or lung problems.
• Very rarely, a second cancer.