Radiotherapy for breast cancer

What is radiotherapy?

Radiotherapy uses high-energy rays to destroy cancer cells, while doing as little harm as possible to normal cells. You may be given it to reduce the risk of breast cancer coming back in the breast, chest or lymph nodes.

Radiotherapy after breast-conserving surgery

If you have breast-conserving surgery, your cancer specialist will recommend you have radiotherapy to the breast after your operation. Some women have an extra dose to the area where the cancer was (a booster dose).

You usually start radiotherapy four weeks after surgery unless you’re having chemotherapy. Radiotherapy is given after chemotherapy.

Radiotherapy after a mastectomy

Some women have radiotherapy after a mastectomy. This depends on the risk of the cancer coming back in the chest area. Your cancer doctor may recommend radiotherapy to your chest if:

  • the cancer was large
  • the cancer was high-grade
  • several lymph nodes in the armpit contained cancer cells or there were cancer cells in the fatty tissue surrounding affected nodes
  • there were cancer cells close to the edges of the removed breast tissue
  • there were cancer cells in the lymph vessels in the breast.

Radiotherapy to the lymph nodes

If the surgeon removed some lymph nodes from your armpit and they contained cancer, you may have radiotherapy to the rest of the nodes. Some women also have radiotherapy to the lymph nodes close to the breast. This can include nodes in the armpit, above the collarbone and by the breastbone (sternum).

We have more information about radiotherapy.

Back to Radiotherapy explained

Possible side effects

There are things you can do to help manage the possible side effects of radiotherapy treatment.