Radiation therapy — also called radiotherapy — is a highly targeted, highly effective way to destroy cancer cells in the breast that may stick around after surgery. Radiation can reduce the risk of breast cancer recurrence by about 70%. Despite what many people fear, radiation therapy is relatively easy to tolerate and its side effects are limited to the treated area.
Your radiation treatments will be overseen by a radiation oncologist, a cancer doctor who specializes in radiation therapy.
Radiation therapy uses a special kind of high-energy beam to damage cancer cells. These high-energy beams damage a cell’s DNA, the material that cells use to divide. Over time, the radiation damages cells that are in the path of its beam — normal cells as well as cancer cells. But radiation affects cancer cells more than normal cells. Cancer cells are very busy growing and multiplying — two activities that can be slowed or stopped by radiation damage. And because cancer cells are less organized than healthy cells, it’s harder for them to repair the damage done by radiation. So cancer cells are more easily destroyed by radiation, while healthy, normal cells are better able to repair themselves and survive the treatment.
There are two different ways to deliver radiation to the tissues to be treated:
Tissues to be treated might include the breast area, lymph nodes, or another part of the body.
Radiation is an important and often necessary form of anti-cancer therapy because it is able to reduce the risk of recurrence after surgery. Although it’s quite possible that your surgeon removed all the cancer, breast cancer surgery cannot guarantee that every last cancer cell has been removed from your body.
Individual cancer cells are too small to be felt or seen during surgery or detected by testing. Any cells that remain after surgery can grow and eventually form a new lump or show up as an abnormality on a test such as a mammogram.
Research has shown that people who are treated with radiation after lumpectomy are more likely to live longer, and remain cancer-free longer, than those who don’t get radiation. In one large study, women who didn’t get radiation after lumpectomy were shown to have a 60% greater risk of the cancer coming back in the same breast. Other research has shown that even women with very small cancers (1 centimeter or smaller) benefit from radiation after lumpectomy.