Side Effects of Radiation Therapy for Breast Cancer
Radiation therapy is often used to treat breast cancer after surgery. The doses of radiation used to destroy cancer cells can also hurt normal cells. The damage to these normal cells is the cause of the common side effects of radiation treatment. The possible side effects of radiation therapy are directly related to the area of the body being treated. Side effects are caused by the cumulative effect (total effect over time) of radiation on the cells, which is why most patients do not experience any side effects until a few weeks into their treatments. While side effects may be unpleasant, there are treatments to help deal with them. Most side effects are temporary, disappearing slowly over time after therapy is complete.
Most radiation oncologists see their patients at least once a week while the patient is receiving treatment. This visit with the healthcare team is a chance for the patient to ask questions, discuss any side effects, and find ways to help relieve side effects. However, you can report concerning symptoms anytime to the treatment team.
Short Term Side Effects
The following list includes some of the most common side effects of radiation therapy for breast cancer. Remember that the treatment can affect each patient differently and you may not experience these problems. Talk with your care team about what you can expect from your specific treatment.
- Skin irritation: Your skin may become red, irritated, dry, or sensitive. This may start to look like a sunburn. The skin may also become darker under the arm and under the breast. In more severe cases, the skin can peel, and moist ulcers can occur. Treat the skin gently to avoid further irritation, and bathe carefully using only warm water and mild soap. Avoid perfumed or scented lotions or soaps, as these may cause further irritation. Avoid spending too much time in the sun, which can worsen the irritation.
- Mild fatigue that generally gets better a month or two after treatment ends.
- Some patients have mild tenderness in the breast or chest wall.
- Some patients have swelling to the ipsilateral arm (the arm that's closest to the area being treated) that may make the movement of that arm more difficult. Any swelling should be brought to the attention of your oncology team.
- Reduced blood counts, including neutropenia (low white cell count), anemia (low red cell count), or thrombocytopenia (low platelet count).
Long-term Side Effects
The side effects discussed above tend to happen during treatment, up until a few months after treatment. Long-term effects can happen months to many years after cancer treatment and the risks vary depending on the areas included in the field of radiation and the radiation techniques that were used.
Though the risk is low, you should be aware of these possible long-term effects:
- There is a low risk of developing a second cancer in or near the radiation field. These are called secondary cancers, and they develop as a result of the exposure of healthy tissue to radiation. Modern radiation techniques are designed to limit this exposure, but it is not always possible to prevent all exposure and still achieve the desired outcomes. Yearly mammograms are important.
- Radiation to the breast, chest wall, or reconstructed breast may cause permanent changes in the skin, including a darkening or "tanning" of the skin. It can also cause fibrosis, a thickening or scarring of an area of tissue in the breast.
- There can be damage to the nerves, leading to pain or loss of strength or feeling in the arm, on the side that was treated.
- Damage to the drainage (lymphatic) system in the area can lead to chronic swelling, called lymphedema. The risk of lymphedema is highest for patients who also had surgical lymph node dissections and, to a lesser extent, sentinel node biopsy. A survivor with lymphedema who develops pain or redness in the arm, especially with fever, should be seen by the care team right away, as it could be a serious infection.
- Survivors of breast cancers, particularly left-sided breast cancers, may be at increased risk for developing cardiac (heart) problems. Your radiation oncologist will pay close attention to minimizing the amount of radiation dose to the heart. You can reduce the risk of heart problems by regularly exercising, having good dietary habits, and seeing your primary care provider for checkups.
- There is a risk of lung injury under the treated breast, which is called radiation pneumonitis. To avoid this, the amount of radiation to the lungs is minimized by using different breast treatment techniques. Symptoms of pneumonitis to report to your provider include shortness of breath, dry cough, chest tightness, and flu-like symptoms.
- Radiation can cause small cracks (fractures) in the bones that are in the treatment field. If any trauma occurs (falls or accidents) notify your care team right away.
After treatment, talk with your oncology team about receiving a survivorship care plan, which can help you manage the transition to survivorship and learn about life after cancer. You can create your own survivorship care plan using the OncoLife Survivorship Care Plan. For more information about the long-term effects of radiation therapy for breast cancer, read our article, Survivorship: Late Effects after Radiation for Breast Cancer.
American Society of Clinical Oncology (ASCO). (2020). Breast Cancer: Types of Treatment. Retrieved from https://www.cancer.net/cancer-types/breast-cancer/types-treatment.
The American Cancer Society. (2019). Radiation for Breast Cancer. Retrieved from https://www.cancer.org/cancer/breast-cancer/treatment/radiation-for-breast-cancer.html.