Radiation therapy for breast cancer may cause short-term side effects, including pain, fatigue, or skin changes, or long-term side effects, such as breast changes and nerve damage.

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

Radiation therapy can use external beam radiation, which involves a doctor applying radiation from an external machine to the breast and surrounding tissue.

Alternatively, radiation therapy can involve internal radiation (brachytherapy), which entails placing a small radioactive pellet into the body for a short period.

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

Short-term side effects may occur during the treatment or shortly afterward. The duration may depend on the type and dose of the radiation, but they typically resolve within a few months.

Potential short-term side effects include:

Long-term side effects occur months or years after treatment has ended and may include:

Radiation therapy may also affect a person’s breast reconstruction options and ability to breastfeed from the affected breast.

According to the American Cancer Society (ACS), less common side effects of breast cancer radiation therapy include:

  • Brachial plexopathy: Radiation to the breast or chest wall can damage the nerves that run through the arm, wrist, and hand. Nerve damage can cause numbness and tingling, pain, or weakness in the area.
  • Rib fracture: It is possible for radiation therapy to weaken the ribs, making them more prone to break or fracture.
  • Lung problems: Radiation can cause lung inflammation. 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.
  • Heart problems: If a doctor applies radiation to the left side of the chest, it can cause an irregular heartbeat, heart valve damage, and hardened arteries, which may increase the risk of a heart attack.
  • Angiosarcoma: Angiosarcoma is a very rare complication of radiation therapy for the breast. It is another type of cancer that may occur 8 to 10 years after the radiation therapy.

However, the ACS notes that modern radiation therapy equipment and procedures have reduced the risk of many of the above complications.

Learn what to expect during radiation therapy for breast cancer.

Generally, 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 short-term side effects, such as fatigue.

The ACS recommends the following strategies to manage side effects:

  • getting plenty of rest
  • speaking with an employer about taking time off, if necessary
  • wearing loose clothing
  • avoiding scratching or rubbing the skin
  • using sun protection when outside
  • washing with lukewarm water and mild soap
  • avoiding wearing a bra, or wear a soft, cotton bra without an underwire

A healthcare professional can offer specific management tips for the side effects a person experiences. This may include exercises to manage shoulder stiffness or products to relieve uncomfortable skin changes.

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 can expect some side effects, but most will be mild and resolve over time.

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

If side effects affect a person’s quality of life, they need to consult a doctor, who can recommend ways to reduce discomfort.

Radiation therapy may cause side effects that vary according to the duration and type of radiation treatment. Short-term side effects may include fatigue, skin changes, and hair loss in the affected area.

However, some people may also experience long-term side effects or complications, including changes to the breast, a higher risk of rib fractures, and difficulty breastfeeding.

People need to speak with their healthcare team if they experience side effects from radiation therapy. A healthcare team can adjust the treatment plan or suggest management strategies to relieve the side effects.