How does a brain tumor affect the body?

Diana Meeks
Diana Meeks on behalf of Sigma Nursing
Family Practitioner

Brain tumors can happen anywhere in the brain. As the cells mutate and the tumor grows, it can then damage other parts of the brain, whether the tumor is deemed cancerous or benign. A tumor that might otherwise be considered harmless in any location other than the brain can seriously affect the body because of the possible damage to the rest of the brain. As a tumor grows, it could affect hearing or speech. Arms and legs may become numb and lose sensation. Many bodily functions may be affected. Additional damage to the brain can occur since the skull is solid and can't "give" as the tumor grows.

Dr. Isaac Yang, MD

A brain tumor by itself doesn’t directly affect the body. It is quite rare for a brain tumor, even when malignant, to travel (metastasize) outside the brain. What brain tumors do is affect either the brain itself or the spinal cord by compressing and compromising the function of the brain that it involves. The brain and spinal cord are responsible for thought and body coordination and movement. So, based on what part of the brain the tumor is affecting, the brain tumor will have different influences on the body, including movement, coordination and regulation of hot and cold.

Brain tumors can interfere with cognitive functioning and cause personality changes. Depending on their location, they can trigger other symptoms, such as headaches, seizures or vomiting. But the first symptoms of slow-growing tumors frequently resemble dementia, especially in older people. Brain tumors may be malignant (cancerous) and therefore capable of invading surrounding tissue. Or they may be benign (self-contained) and cause symptoms only when compressing neighboring brain tissue.

Tumors within any part of the brain may cause increased pressure within the skull. This can be caused by growth of the tumor, swelling in the brain or blockage of the flow of cerebrospinal fluid. Increased pressure can lead to general symptoms such as:

  • Headache
  • Nausea
  • Vomiting
  • Blurred vision
  • Balance problems
  • Personality or behavior changes
  • Seizures
  • Drowsiness or even coma

About half of people with brain tumors will have seizures at some point. The type of seizure may depend on where the tumor is. Sometimes this is the first sign of a brain tumor, but fewer than 1 in 10 first time seizures are caused by brain tumors. Tumors in different parts of the central nervous system can cause different symptoms. But these symptoms can be caused by any disease in that particular location in the brain—they do not always mean it’s cancer.

  • Tumors in the parts of the brain that control movement or sensation may cause weakness or numbness of part of the body.
  • Tumors in or near the parts of the brain responsible for language may cause problems with speech or even understanding words.
  • Tumors in the front part of the brain can sometimes affect thinking and personality.
  • Tumors in an area of the brain called the basal ganglia typically cause abnormal movements and an abnormal positioning of the body.
  • If the tumor is in the cerebellum, where coordination is controlled, a person might have trouble with walking or other everyday functions, even eating.
  • Tumors in the back part of the brain, or around the pituitary gland, the optic nerve, or certain other cranial nerves can cause vision problems.
  • Tumors in or near other cranial nerves might lead to loss of hearing, balance problems, weakness of some facial muscles, or trouble swallowing.
  • Spinal cord tumors can cause numbness, weakness, or lack of coordination in the arms and/or legs, as well as bladder or bowel problems.

The brain also controls functions of many other organs, including the production of hormones. There are many other symptoms that can be caused by brain tumors that aren’t listed here.

Brain tumors can affect the body in different ways, depending on the location. It can cause numbness or weakness in the face, arm, leg or torso. It can cause imbalance, poor coordination of the arms or legs, blindness, hearing loss, vertigo or decrease the ability to speak or understand language. It can cause headache especially if there is associated increased pressure in the brain. It can also cause changes in behavior and seizures.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.