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Side effects of radiation

Radiation kills cancer cells. Unfortunately, radiation can damage or kill normal cells near the site receiving the radiation. This can lead to the side effects that are seen with radiation. These vary by the dose, length, and location of the radiation. For people who experience side effects, there may be options for minimizing or eliminating some of these side effects. It's important to talk with your doctor about possible treatment side effects and how they can be managed.

Short-term effects

Some of the more common short-term side effects of radiation may include:

Most of the symptoms above are temporary and resolve by several months after radiation ends. 

Long-term effects

Some of the longer term effects may include:

Bowel effects

Short term problems from radiation to the pelvic, or rectal may include rectal pain, burning, painful bowel movements and diarrhea. There are medications that can help with these symptoms, which are usually temporary. 


Fatigue may be caused by cancer or treatments, including radiation. Although no medications can counteract fatigue, you can take steps to try to improve your energy level, including: 

  • making sure that your diet is balanced and provides you with adequate nutrition. As your doctor for a referral to a nutritionist if you need help figuring out your nutritional needs.
  • making sure that you get adequate sleep. 
  • trying to stay physically active, which can help improve your energy level. 

Fertility issues

Some radiation therapy can cause early menopause in women and low sperm counts in men. These changes may be temporary or permanent. Options are available for men and women who are diagnosed with cancer and wish to preserve their fertility. It's important to discuss fertility preservation before starting treatment for cancer. 

Heart damage

Radiation to the chest may cause heart damage later. Your oncologist may run tests to make sure that your heart function is normal before, during and after radiation. 

Low blood cell counts

Some radiation may damage the bone marrow, where blood cells are made. Your oncologist may test your blood during and after radiation, to make sure that your blood counts do not drop too low. 

is fluid buildup and swelling that can develop in the arms, legs or other part of the body,  after radiation therapy. The swelling and fluid may be mild to severe and can cause pain, infection and loss of mobility. can happen immediately or months or years after treatment. 

is usually managed with special massage and compression garments. This is most effective when it is caught early. In some circumstances, that progresses can be managed with surgery. 

Second cancers

On rare occasions, radiation damage to normal cells can cause a new cancer to develop. 

Sexual side effects

During radiation damage to the skin may make sex painful. Your doctor may recommend avoiding sex during radiation treatment. In men, radiation may damage nerves and affect the ability to have erections. This may be a short-term or longer-term problem. Speak to your doctor about options for managing any sexual side effects that persist after treatment ends. 

Skin changes

Radiation can damage skin cells as it passes through the skin to the area being treated. This can lead to pain, swelling, redness, and sunburn-like damage to skin. Overtime, as with a sunburn, the skin may be itchy, dry or flake or peel. There are things you can do to improve the discomfort, such as wearing loose-fitting clothes made of soft fabrics, protecting your skin from sun exposure, using only mild soaps and products approved by your doctor on your treated skin. There may also be medications and creams or ointments that your doctor may prescribe to help ease the skin pain and discomfort from radiation. 

Swallowing problems

Radiation to the chest can cause irritation to the esophagus, which can make eating painful. Certain liquid medications can help to block the pain. 

Urinary effects 

Frequent or painful urination or bladder leakage (incontinence) may occur during radiation to the pelvis or . Damage to the bladder can result in chronic bleeding from the bladder. Your doctor may have medications or strategies such as pelvic floor strengthening to improve incontinence and medication to reduce urinary frequency that persists after treatment ends.

Last updated August 06, 2020