Glioblastoma Multiforme

Definition

Glioblastoma multiforme (GBM) is the most common glioma (a type of brain cancer). It represents nearly one fourth of all primary brain tumors. This cancer starts in the glial cells, which are cells that help nerve cells work.

This condition can develop spontaneously. Less commonly, it can develop from a lower grade, less malignant (cancerous) brain tumor. Most cases are located in the cerebral hemisphere, but the cancer can begin in the spinal cord or brain stem.

If you suspect you have this serious condition, contact your doctor immediately. Early treatment leads to a more favorable outcome.

Brain Tumor

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Causes

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

These factors increase your chance of developing GBM. Tell your doctor if you have any of these risk factors:

• Sex: male (slightly more common in men that women)
• Age: over 50 years old
• Ethnicity: Caucasians, Latinos, Asians
• Having a low-grade astrocytoma (brain tumor), which occasionally develops into a higher-grade tumor
• Having one of the following genetic disorders is associated with an increased incidence of gliomas
  • Neurofibromatosis
  • Tuberous sclerosis
  • Von Hippel-Lindau disease
  • Li-Fraumeni syndrome
  • Turcot's syndrome
• Radiotherapy (association between high-dose ionizing radiation and astrocytoma)

There is inconsistent evidence that electromagnetic radiation and cell phone use are associated with this condition.

Symptoms

Symptoms include:

• New onset headaches—more than 30% of patients
• New onset seizures—20% to 30% patients
• Progressive cognitive dysfunction—depends on the location of the tumor; problems with vision, language, motor function, or sensation may occur
• Personality changes
• Behavioral changes, development of inappropriate behaviors
• Memory loss

Diagnosis

After taking a complete history of your symptoms and completing a physical exam, your doctor may also use the following tests:

• CT scan —a type of x-ray that uses a computer to make pictures of structures inside the brain
• MRI scan —a test that uses magnetic waves to make pictures of structures inside the brain
• Functional MRI (fMRI)—a test that gathers information on blood flow within tumors, gives more information about the tumor and the function of surrounding normal brain tissue
• MRS scan—a test which measures metabolism (of the affected area) in the brain
• Electroencephalogram (EEG) —a test that records the brain's activity by measuring electrical currents through the brain
• Brain biopsy —removal of a sample of brain tissue to test for abnormalities in the brain
• Spinal tap —removal of a small amount of cerebrospinal fluid to check for abnormalities in the brain
• Positron emission tomography (PET) scan and single photon emission tomography SPECT scan—produces images that show the amount of functional activity in the living tissue being studied

Treatment

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

• Radiation treatment is used to further decrease the size of the tumor, usually by about 25% and may be most helpful in improving survival in older patients.
• Chemotherapy also increases survival time and quality of life.
• Steroids to suppress swelling, antiseizure medication to suppress seizures, and pain medications are also used.

Currently, researchers are studying new treatments. These include:

• Immunotherapy
• Anti-angiogenesis (to stop tumors from making new blood cells)
• Molecular therapy
• Gene therapy
• Genetic analysis of the tumor—This is becoming an important tool in determining which therapies are best suited for a given individual. More research needs to be done in these areas.

Unfortunately, overall prognosis is poor. Even with aggressive treatment, few patients survive more than five 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:

• Support group
• Psychotherapy and psychiatry
• Pain management
• Hospice care

Prevention

As the causes of GBM are unknown, there are no preventive measures.