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Radiation for Early-Stage Breast Cancer

Treatment Overview

External beam radiation therapy uses doses of radiation to kill cancer cells. A beam of radiation is aimed at the breast and sometimes the surrounding lymph nodes 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

Radiation therapy for early-stage breast cancer is usually given 5 days a week. The length of time you get radiation can take as little as 5 days up to 6 weeks. Your oncologist will talk with you about how long you will need to have radiation treatment.

The doctor will look at the stage of the tumour and other things. This is to help decide which course may be right for you. Ask your doctor to go over both of these options with you.

Why It Is Done

Radiation therapy 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 cancer in the lymph nodes.

If you've had breast-conserving surgery, you may choose to get hypofractionated radiation. This is a shorter course of treatment. But the doses of radiation are higher.

How Well It Works

Studies have shown that standard and hypofractionated treatment work equally well. Both can keep cancer from coming back in women who have early-stage breast cancer.


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.


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