Side effects of radiation in breast cancer treatment

Although radiation therapy is an extremely effective from of breast cancer treatment, there can be some mild-to-severe side effects of radiation exposure to the breast. Some of these side effects can begin during treatment, while others can arise months or years after the treatment is completed.

The most common side effects of radiation therapy in breast cancer include:

Pain and skin changes

During and just after receiving radiation, the treated breast can become sore. The treated breast may also become rough to the touch, or red (which feels like a sunburn) and/or swollen. Sometimes the skin on the breasts can peel off. There can be moist reactions, where the skin keeps peeling in layers and the area becomes tender and sensitive; this happens commonly in the folds of the skin on the breasts, and on the skin on the bottom side of the breasts.


Fatigue is a very common side effect of radiation therapy. It can present itself during treatment, or months after treatment and continue to last for several weeks or months after the treatment ends.

Breast and skin changes

Over time, patients may experience either firmness or shrinkage of one breast or both breasts. They can also get mild tanning of the skin where the breast was exposed to radiation, or some form of red discoloration, especially around (any) surgical scar(s). These changes can become permanent in nature.


In this condition, fluid collects in the underarm area and other areas where lymph nodes are present, causing them to swell up. Chances of lymphedema are higher in patients who have received adjuvant (post surgical) radiation therapy to the lymph node area, and to patients who have had an axillary lymph node dissection prior to receiving radiation treatment.

Aside from the above-mentioned common side effects, some of the rare side effects of radiation therapy in breast cancer patients, include:

  • Nausea and hair loss (more commonly seen as a side effect of chemotherapy)
  • Rib fractures
  • Heart problems (cardiotoxicity)
  • Lung complications, extending to potential lung cancer due to radiation exposure
  • Nerve problems, such as brachial plexopathy

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