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Side Effects

The side effects you might experience will depend on the part of the body being treated, the dose of radiation given and whether you also receive chemotherapy. Before treatment begins, ask your doctor about possible side effects and how best to manage them. This list doesn't represent all of the possible side side effects.

This is a visual side effects chart showing short and long term side effects. Larger bubbles show higher likelihood of occurrence. To see a larger version, click on the chart.

Brain Tumor Side Effects

For patients who prefer to look at the side effects in text instead of graphics, please see below.

Short term side effects

Side effects are usually temporary and usually go away shortly after treatment ends. Below is a list of possible side effects you might notice during your treatment. 

More likely
  • Fatigue
  • Hair loss
  • Erythema or soreness of scalp
  • Headaches

Less likely

  • Weakness
  • Nausea/vomiting
  • Vision changes
  • Seizures
  • Reactions in ear canal
  • Hearing impairment**
  • Altered taste**
** These side effects are all very uncommon

Long term side effects

​After the short term side effects of radiation therapy resolve, others may become noticeable ​months or years later.

More likely
  • Lethargy
  • Radiation necrosis
  • Neurological symptoms 1-3 months after treatment
Less likely
  • Mental slowing and behavioral changes
  • Abnormal hormone levels (common in areas near the pituitary gland)
  • Permanent hearing impairment**
  • Permanent visual impairment**
  • Dry eye
  • Dry mouth**
  • Cataracts**

** These side effects are all very uncommon

Radiation may also cause short-term memory loss, difficulty thinking and slowness in completing tasks. Some patients benefit from medicine or a specialized radiation technique that can reduce short-term memory loss. Ask your doctor if these options are available for you.

Side effects are different for each patient. Medications may be prescribed to make you as comfortable as possible. If at any time during your treatment you feel discomfort, tell your doctor or nurse.