One common and effective treatment for breast cancer is radiation therapy. However, it does have some side effects.

A doctor may recommend radiation therapy in combination with other treatments, such as surgery and chemotherapy.

There are two main types of radiation treatment:

  • External beam radiation: This involves a doctor applying radiation from an external machine to the breast and surrounding tissue.
  • Internal radiation (brachytherapy): This involves placing a small radioactive pellet into the body for a short period.

The right treatment for breast cancer depends on many factors, including a person’s age and overall health. A doctor will help a person decide on the best option for them.

Read on for more information about the short-term, long-term, and rare side effects of radiation for breast cancer.

Radiation for breast cancer infographic <br>Image credit: Stephen kelly, 2018</br>
Image credit: Stephen Kelly, 2018

Short-term side effects

Short-term side effects occur during the treatment or directly afterward, usually within 6 months.

Common short-term side effects include:

  • Pain: Some people experience mild discomfort or pain around the breast, or stiffness in the shoulder area. Over time, treatments should become less uncomfortable.
  • Skin changes: Skin damage is a common side effect of radiation therapy, and having a good skin care routine is essential during treatment. Changes to the skin can include:
    • color changes
    • peeling or flaking
    • skin that feels tender, dry, itchy or sore
    • blisters
    • excess moisture and weeping
  • Swelling: The breast or surrounding tissue may become swollen or inflamed. Swelling should reduce within a few weeks of the end of treatment.
  • Hair loss in the armpit or chest: When a doctor applies radiation to the lymph nodes in the armpit and chest, it can cause hair loss in these areas.
  • A sore throat: Applying radiation to the lymph nodes around the collarbone can cause a sore throat or difficulty swallowing. These symptoms should improve once the treatment is complete.
  • Fatigue: Radiation can cause someone to feel very tired or fatigued. Being in the hospital and having other treatments, such as chemotherapy, can worsen this fatigue. It is important to sleep and rest as much as possible during treatment.

Long-term side effects

Long-term side effects occur months or years after treatment has ended.

Long-term side effects can include:

  • Breast changes: The breasts may shrink or become more dense after radiation. Some women have reported problems breastfeeding.
  • Brachial plexopathy: Radiation to the breast or chest wall can sometimes damage the nerves that run through the arm, wrist, and hand. Nerve damage can cause numbness, pain, or weakness in the area.
  • Lymphedema: Lymphedema is swelling of the arm, hand, or chest. Radiation can sometimes damage nearby lymph nodes, leading to a buildup of lymph fluid.

Rare side effects

Rare side effects of radiation can include:

  • Nausea: Radiation can cause nausea, but this side effect is extremely rare.
  • Rib fracture: It is possible for radiation therapy to weaken the ribs, making them more prone to break or fracture. However, with new treatment protocols in practice, this is very rare.
  • Heart problems: If a doctor applies radiation to the left side of the chest, it can damage the heart. However, with new protocols in place, this is also rare.
  • Lung problems: Very rarely, radiation causes inflammation in the lungs. The medical term for this is radiation pneumonitis, and symptoms include shortness of breath, a cough, and a low-grade fever, which will go away over time.
  • A second cancer: In very rare cases, radiation exposure can increase the risk of developing a second cancer.

Coping with side effects

Woman being comforted after chemotherapy
Having a loved one help with everyday tasks can help reduce stress and fatigue.

The benefits of having radiation therapy for breast cancer outweigh the risks. However, the side effects can be uncomfortable.

Asking friends and family to help with everyday activities during treatment can help a person accommodate some common side effects, such as fatigue.

Using heating pads and ice packs may help a person cope with pain and soreness following radiation therapy.

Wearing loose clothing and applying an unscented moisturizer can help reduce discomfort caused by skin changes.

To reduce stress and fight fatigue, a person can also try:

  • meditation
  • eating a nutritious diet that includes lean protein and plenty of vegetables
  • doing light exercise every day, even if it is a short walk
  • getting regular massages
  • yoga
  • reducing commitments
  • keeping a mood and symptoms diary
  • joining a support group
  • seeing a therapist

It is crucial to report any side effects to a doctor or nurse, especially if a person is experiencing them for the first time.


Radiation therapy can be a very effective treatment for breast cancer. A person should expect some side effects, but most will be mild and resolve over time.

It is essential to communicate any side effects to the medical team, to ensure that a person is not experiencing a symptom of something more serious.

If side effects are impacting a person’s quality of life, they should speak to a doctor, who may be able to recommend ways to reduce discomfort.