Radiation Therapy for Breast Cancer: Benefits, Side Effects and Risks

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Radiation therapy, also sometimes referred to as radiotherapy, often plays a role in the treatment of breast cancer. For many patients, it can play a positive role in breast cancer care, reducing the likeliness that cancer will return after a tumor has been surgically removed. Radiation works by destroying cancer cells and preventing cancerous cells from reproducing. While radiation therapy for breast cancer has many benefits, there are risks involved as well. Understanding possible side effects and what to expect from treatment is important for all cancer patients.

External or Internal

There are two different types of radiation that are used to treat breast cancer patients. The first and most common is external beam radiation. This technique may be used after a lumpectomy or mastectomy. A linear accelerator is used to administer high-energy radiation to the site of the cancer. Treatments are given over a period of several weeks.

Internal radiation, which may be used after a lumpectomy, is a newer form of radiotherapy for breast cancer. Very small ‘seeds’ of radioactive material are put within the body where the cancer had previously existed. While the seeds are in place (time varies depending on the strength of the dose used) a patient remains in the hospital and is radioactive. Once treatment is over, the seeds are removed.


The benefits of radiotherapy are that for many women it has contributed to ridding the body of cancer or at least to slowing the progression of cancer. It is not used on its own, but as a supplementary treatment after surgery for breast cancer. When the tumor is removed, radiation can be used to eliminate any remaining cancerous cells.

Another benefit of radiotherapy is that if used only when appropriately, it is considered to be relatively safe. While there are side effects, they are not as intense as other forms of treatment, such as chemotherapy.

Side Effects and Risks

While radiation therapy is used to treat breast cancer in many cases, it is only used when it is well-suited for the patient and in amounts that are tolerable to the patient. This is because living tissue can only handle so much radiation exposure and there are side effects of use. While radiotherapy does kill cancer cells, it kills healthy cells as well.

The most common and usually the most bothersome side effect of external radiation is skin irritation. The skin around the site of the radiotherapy will become red, dry and possibly painful. This irritation does clear up over time. Other side effects include fatigue during treatment and reduced blood counts.

What risks are involved from using radiation therapy? Although very unlikely, radiation treatments may be associated with the formation of other tumors. Some patients do experience scarring on the site of the radiation. Lung inflammation, damage to the heart and rib fractures are other possible problems, but with newer forms of treatment they are extremely unlikely.


According to BreastCancer.org, this form of treatment can reduce the risk of the cancer returning by as much as 70 percent. When appropriate, such as after surgery for a patient who has not already had radiation to the same area, using radiation therapy for breast cancer can increase the likeliness of survival. Radiation does not save, nor even benefit every patient, but it is and has been an important part of treatment for many patients. Understand what happens to the body, what the benefits are, what the risks are and if treatment is given, be sure to do everything you can to take care of your well-being during therapy.


WebMD. https://www.webmd.com/breast-cancer/radiation-therapy-overview

Breast Cancer.org. https://www.breastcancer.org/treatment/radiation/

National Cancer Institute. https://www.cancer.gov/cancertopics/factsheet/Therapy/radiation