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Potential Side Effects of Radiation Therapy for a Brain Tumor

Even though doctors try to be precise when giving radiation therapy, some normal cells are almost always exposed to the effects of radiation. This causes side effects.

Here are some of the side effects of radiation therapy for brain tumors.

  • Decreased sex drive

  • Headache

  • Intolerance of cold

  • Nausea and vomiting

  • Tiredness and fatigue

  • Trouble thinking and remembering

Sometimes, dead brain tissue will form at the site of the radiation. This is called radiation necrosis. Most of the time, the mass of dead brain tissue contains both cancerous and healthy cells. Radiation necrosis can take anywhere from months to years to develop.

If you have problems from the mass from radiation necrosis, you may need to have it removed with surgery. Here are examples of some problems it may cause.  

  • Dementia

  • Headache

  • Seizures

It is not always easy to tell the difference between radiation necrosis and cancer that has come back. A special brain scan, called a positron-emission tomography (PET) scan, can sometimes tell the difference between dead tissue and living cancer tissue. But often a biopsy is the only way to tell for sure.

Radiation can also affect your genes. As a result, after radiation, you have a small risk of getting a second cancer. This second cancer usually occurs many years later. The risks should not keep you from having radiation if you need it.