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  • Side Effects of Radiation Therapy


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    Radiation Therapy and Side Effects
    Fact Sheet

    Radiation therapy has some side effects. Some begin during treatment, while others may occur months or even years later.

    Short-term side effects

    Most often, side effects from radiation therapy begin within a few weeks of starting treatment and go away within a few weeks after treatment ends [15].  

    During and just after treatment, your treated breast may be sore. Mild pain relievers such as ibuprofen or acetaminophen can ease breast tenderness.  

    The treated breast may also be rough to the touch, red (like a sunburn) and swollen. Sometimes the skin may peel, as if it were sunburned. Your radiation oncologist may suggest special creams to ease this discomfort. Sometimes the skin peels further and the area may become tender and sensitive (called a moist reaction). This is most common in the skin folds and the underside of the breast. If this occurs, let your oncologist or nurse know, and he/she can give you creams and pads to make the area more comfortable until it heals.  

    Fatigue is common during radiation therapy and may last for several weeks after treatment ends.  

    Nausea is not common with radiation therapy. And, you shouldn’t lose the hair on your head. However, you may lose some hair under the arm or on the breast or chest area receiving radiation (this may be an issue for men with breast cancer).  

    Learn more about easing pain related to radiation therapy.  

    Long-term side effects

    Over time, you may notice firmness or shrinkage of the breast. You may also have mild tanning of the skin in the treated area or red discoloration, especially around the surgical scar(s). These changes are often permanent.  

    Women who have lymph nodes in the underarm area (axillary nodes) removed may develop lymphedema. Lymphedema is a condition in which fluid collects in the arm (or other areas such as the hand, fingers, chest or back), causing it to swell. The chances of getting lymphedema are greater if your treatment includes both [15]:

    • Removal of a large number of axillary nodes during breast cancer surgery
    • Radiation therapy to the axillary or supraclavicular (above the collarbone) nodes

    Lymphedema is also more likely in women who are overweight [16].  

    Learn more about lymphedema.   

    Rare side effects

    Although rare with modern radiation therapy, treatments can injure the normal tissues near the radiation field of the breast or chest wall. The following are rare side effects:

    • Rib fracture occurs when the radiation weakens the rib cage near the treatment area.

    • Heart problems can develop when radiation therapy is given to the left side of the chest. If they happen, heart problems arise years after radiation therapy is finished.

    • Radiation pneumonitis (NOO-moh-NY-tis) is an inflammation of the lungs that can cause shortness of breath, a dry cough and low-grade fever. Severe symptoms can often be relieved by anti-inflammatory drugs. Radiation pneumonitis almost always goes away with time.

    • Brachial plexopathy (BRAY-kee-ul pleks-AH-path-ee) can happen when radiation damages nerves in the upper chest. It may cause tingling, pain and weakness in the affected hand and arm that is usually permanent.

    These conditions may occur a few months or years after radiation therapy.

    Radiation therapy and risk of a second cancer

    In rare cases, radiation therapy can cause a second cancer. The most common cancers that have been linked to radiation therapy are sarcomas (cancers of the connective tissue) [17-18]. However, the risk of a second cancer is very small and the benefits of radiation therapy almost always outweigh the risks.


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    Updated 04/30/14


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