Side effects from radiation therapy to the brain

Stereotactic radiosurgery is often used when cancer is in only one or a few sites in the brain. (This radiation treatment gives a large dose of radiation to a small tumor area.) Side effects depend on where the radiation is aimed. Some side effects might show up quickly, but others might not show up until 1 to 2 years after treatment. Talk with your radiation oncologist about what to watch for and when to call for help.

Sometimes the whole brain is treated with radiation when cancer is in many areas. This may also be done to keep cancer from spreading to the brain.

Radiation to the brain can cause these side effects:

  • Headaches
  • Hair loss
  • Nausea
  • Vomiting
  • Extreme tiredness (fatigue)
  • Hearing loss
  • Skin and scalp changes
  • Trouble with memory and speech
  • Seizures

Some of these side effects can be caused by swelling of the brain from the radiation. Medicines are usually given to prevent brain swelling, but it’s important to let your cancer care team know about headaches or any other symptoms. Delayed effects (usually 1 or 2 years later) of brain radiation may be caused by death of brain tissue. These delayed effects can include serious problems such as memory loss, stroke-like symptoms, and poor brain function.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Last Medical Review: June 30, 2015 Last Revised: June 30, 2015

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