Radiation Side Effects

Radiation therapy  is a common treatment for breast cancer. It is used after almost all lumpectomies  and sometimes after mastectomy  to kill any remaining cancer cells in the breast area. The treatment usually involves exposing the breast, or part of the breast, to high energy x-rays. 

If you receive radiation therapyinfo-icon, you may experience one or more of the side effects it is known to cause. Many are minor and will go away after treatment is finished. And because radiation therapy is a local treatment most side effects will be seen in the breast being treated, not throughout your whole body. 

Always tell your doctor how much and in what ways a side effectinfo-icon is affecting your daily life, or if it lasts longer than expected. 

Skin Changes

Radiation therapyinfo-icon most commonly affects the skin of the breast and nearby areas. During treatment you may find your skin becomes dry and irritated. It may change color or become flaky. These are usually side effects of external beam radiation. They are still possible, though less likely, with internal partial-breast radiation.

If you notice new side effects a year or more after radiationinfo-icon treatment ends, report them to your doctor.

These skin changes can be distressing, but you can care for your skin during treatment and ease most side effects:

  • Avoid tight clothes and rough fabrics such as corduroy or wool.
  • Be gentle when you wash. Choose mild soap like Ivory, Dove or Castille, and warm water. When drying, pat gently with a clean towel.
  • Avoid direct sunlight. Sun exposure can make skin reactions worse or result in severe sunburn.
  • Do not rub or scratch the area.
  • Do not put on a bandage or medical tape on the treated area.
  • Do not use makeup or shaving cream on the area.
  • Do not apply lotions or creams unless they have been recommended or approved by your doctor. There are creams and lotions available to keep your skin moisturized. Talk to your doctor about which are safe to use after radiation therapy. 


Radiationinfo-icon can leave you with less energy than usual. Sometimes it can interfere with your daily tasks. Fatigue related to cancer treatment is different than being exhausted from a long day at work or from exercise, because it’s constant and seems like it comes out of nowhere.

Fatigueinfo-icon may get worse each time you go for a radiation treatment. But your energy should come back after treatment ends.

Consider trying these tricks to help you manage your energy while you are receiving radiation therapyinfo-icon. This may mean doing less, or allowing friends and family to help with some tasks like shopping or cleaning.

Swelling and Soreness

Fluid may build up in your breast during radiation therapyinfo-icon, changing the size and shape of your breast and causing soreness. Like many side effects, this should be temporary.

In some cases, radiationinfo-icon may cause lymphedemainfo-icon, a lifelong conditioninfo-icon where lymphinfo-icon fluid can build up and cause swelling in the breast, chest, shoulder or arm. Lymphedema is a result of damage to the lymph nodes because of surgeryinfo-icon or radiation therapy. Learn more about lymphedema, what causes it and how to manage it here. 

Less Common Side Effects

Shortness of Breath, Chest Pain and Coughing

Though rare, it is possible to develop an inflammationinfo-icon of the lung after radiationinfo-icon called radiation pneumonitis. This is an inflammation of lung tissueinfo-icon that can cause shortness of breath, chest pain and coughing. Radiation pneumonitis usually appears 6 weeks to 6 months after finishing radiation therapyinfo-icon. It does not always have symptoms and may be discovered by a chest x-rayinfo-icon.

Pneumonitis is usually treated with steroids and most people recover without any ongoing effects.

Anyone, with or without cancer, should see a doctor if they experience shortness of breath, chest pain or excessive coughing, as these can be symptoms of many serious illnesses and may not be side effects of cancer treatment. Your doctor will be able to tell you if radiation therapy is causing these side effects.

Heart Damage

Radiation therapy can have an effect on your heart in rare cases, especially when the breast being treated is on the left side, where the heart is located. Radiation can cause the arteries, which carry blood from the heart to the lungs and other parts of your body, to harden, raising the risk of a future heart attack.

Other problems that radiation may cause in very few cases include rib fractures and nerveinfo-icon damage that results in tingling or weakness in the arm on the side being treated.

Other Cancers

In very rare cases, radiation therapy can lead to another cancer, like certain carcinomas and lung cancer. The risk is very small and doctors generally find the benefits radiation has in killing breast cancer cells are much greater than the risk of it causing another cancer.

June 12, 2018