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Radiation therapy (also called "radiotherapy") is the use of high energy x-rays to kill cancer cells. It may help reduce your chances of having cancer come back in other parts of your body.

How it works

The radiation beam of the x-ray machine will direct the rays to the designated areas on your body. The rays emitted to the specified area will damage the cells so that they eventually die. If there are healthy cells in the area, they’ll die too, which is why the radiation oncologist is very careful in aiming the beam only where it’s required. Healthy, normal cells repair themselves from radiation damage more completely than cancer cells do.

Before your first treatment, you’ll have a planning session with your radiation oncologist. This session (or sessions) is very important as your radiation oncologist decides exactly where the x-ray machine will be directed. A marker will be used to mark the places on your body where the radiation should go. Be careful not to wash these markings off as they’ll be needed for the course of your treatment. For this procedure, you’ll be lying down and a device will help keep your breast(s) in the same position for every treatment session.


The treatment schedule

You may start radiation treatment after surgery, or during or after chemotherapy. Your treatment schedule depends on what you and your doctor believes is best for you.

Your radiation therapy will also depend on the amount of tissue being treated. You usually get treatment every day, from Monday to Friday, for three to six weeks, and it takes just a few minutes each time.

Who may benefit from radiation therapy?

Radiation therapy is usually considered when:

  • You’ve had a breast-sparing lumpectomy or partial mastectomy.

  • If there was cancer in the lymph nodes.

  • You’ve had a modified radical mastectomy, where there is a high risk of cancer returning on the chest wall or lymph nodes.

  • You’ve been advised not to have surgery but need treatment for cancer that has advanced in your breast.

  • You are at high-risk of local breast cancer recurrence

  • You have a recurrence of cancer on your chest wall or the cancer has spread to other areas, such as the bones, lymph nodes or brain.

External beam radiation therapy is almost always offered after breast-conserving surgery.

Radiation therapy may also be offered after a mastectomy if:

  • The tumour is larger than 5 cm in diameter.

  • The cancer has invaded the skin or muscles of the chest wall.

  • Cancer was found in the lymph nodes.

  • There were cancer cells in the tissues close to where the breast was removed.