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Glioblastoma Multiforme(GBM; Brain Tumor; Malignant Astrocytoma)

Pronounced: GLEE-oh-blass-TOE-mah


Glioblastoma multiforme (GBM) is the most common glioma—a type of brain cancer. This cancer starts in the glial cells, which are cells that help nerve cells work.

This condition can develop suddenly. It can also develop from a lower-grade, less cancerous brain tumor. Most cases are located in the cerebral hemisphere of the brain. The cancer can also begin in the spinal cord or brain stem.

Brain Tumor

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GBM originates from astrocytes, which are a type of glial cell. The factors that cause normal-functioning astrocytes to become cancerous is not well understood.

Risk Factors

GBM is more common in people over 50 years old, especially those who are Caucasian, Hispanic, and Asian. Factors that increase your chance of developing GBM include:

  • Having a low-grade brain tumor, which occasionally develops into a higher-grade tumor
  • Having one of the following genetic disorders:
  • History of radiation therapy
  • Occupational exposures in the synthetic rubber or petroleum-refining industries
  • Exposure to vinyl chloride or pesticides
  • History of CT scans during childhood

Symptoms may vary depending on the location or size of the tumor. In general, symptoms may include:

  • New onset headaches
  • New onset seizures
  • Progressive cognitive dysfunction
  • Problems with vision, language, motor function, or sensation may occur
  • Progressive neurological deficits, including weakness or numbness
  • Personality changes
  • Behavioral changes, development of inappropriate behaviors
  • Memory loss

You will be asked about your symptoms and medical history. A physical exam will be done.

Images and scans may be taken of your brain. This can be done with:

Your brain activity may be measured. This can be done with:

Your bodily fluids and tissues may be tested. This can be done with:

  • Biopsy—tissue samples are taken and examined under a microscope
  • Lumbar puncture—to evaluate the cerebrospinal fluid that surrounds the brain and spinal cord

Surgery is often done to confirm diagnosis and relieve headache, but doctors cannot completely remove the cancer. Other types of treatment may include:

  • Radiation therapy—to further decrease the size of the tumor
  • Chemotherapy—to increase survival time and quality of life
  • Steroids to suppress swelling
  • Antiseizure medications to suppress seizures
  • Pain relievers

Even with aggressive treatment, few patients survive more than 5 years after diagnosis. However, there is evidence that medical and surgical intervention can increase life expectancy and improve quality of life.

A multi-disciplinary approach is important for you and your family. This approach may involve:


There are no current guidelines to prevent GBM because the cause is unknown.


American Brain Tumor Association

National Brain Tumor Society


Brain Tumour Foundation of Canada

Canadian Cancer Society


General information about adult primary central nervous system (CNS) tumors. National Cancer Institute website. Available at: Updated January 27, 2016. Accessed September 6, 2016.

Glioblastoma. EBSCO DynaMed Plus website. Available at: Updated May 16, 2016. Accessed September 26, 2016.

Last reviewed May 2016 by Mohei Abouzied, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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