Glioblastoma multiforme (GBM), or simply glioblastoma, is a highly aggressive type of cancer that starts in your brain or spinal cord. It tends to spread quickly, and people with GBM often have poor outlooks.

Glioblastoma affects about 1 in 100,000 people per year. It makes up about 45.2% of cancerous tumors that start in your brain and spinal cord.

Researchers are still trying to understand what causes it. As of now, no specific risk factors have been identified other than radiation exposure to the brain.

Glioblastoma is considered incurable, and only a small percentage of people live longer than 5 years. The World Health Organization classifies glioblastoma as a grade 4 tumor, which is the category for cancers that spread the quickest.

Treatment usually involves surgery with both radiation therapy and chemotherapy.

Read on to learn more about this rare type of cancer, including symptoms, your potential outlook, and treatment options.

Glioma is a general term that refers to any type of cancer that starts in glial cells in your brain or spinal cord. Glial cells support neurons that pass electrical information.

Glioblastoma is a highly aggressive form of glioma. It’s also called grade 4 astrocytoma or high-grade astrocytoma since it develops in a type of glial cells called astrocytes. It makes up more than 60% of brain tumors in adults.

About 95% of cases of glioblastoma develop in a part of your brain called the supratentorial region, which is the upper part of your brain that doesn’t include the cerebellum or brainstem.

Symptoms of glioblastoma vary depending on where your tumor develops. Headaches are the most common symptom and occur in 30% to 50% of people.

Other symptoms can include:

More than half of people diagnosed with glioblastoma have symptoms for about 3 to 6 months before their diagnosis. Symptoms may persist for years in people who have glioblastoma that evolves from a lower-grade astrocytoma.

Symptoms can also develop quickly in days or weeks and resemble those of a stroke. Glioblastoma can also rarely trigger a stroke if it compresses healthy brain tissue.

In about 80% of people, glioblastoma develops spontaneously with no clear cause. For the other 20%, in develops from less aggressive tumors called astrocytoma and oligodendroglioma.

Glioblastoma can develop at any age, but it’s most often diagnosed in people between the ages of 55 to 60. It seems to be more common in developed countries than in less developed countries, likely due to underdiagnosis in developing countries.

Researchers haven’t found any specific risk factors that account for most glioblastomas, and most people don’t have a family history. Some pesticides and agricultural agents are suspected as possible contributors, but there’s not enough evidence to find a definitive link.

Glioblastoma may develop after previous radiation exposure, and about 300 cases of radiation therapy-induced brain tumors have been reported since the mid-seventies. Tumors seem to develop in the region of the brain where radiation therapy was administered.

Doctors usually start the diagnostic process by reviewing your medical history and performing a physical exam. Your physical exam will likely involve a neurological exam. In this exam, doctors check aspects of your health such as your coordination, eyesight, and movement to look for potential issues with your central nervous system.

If your doctor suspects a neurological abnormality, they’ll order imaging scans of your brain.

Magnetic resonance imaging (MRI) with a contrast dye is considered the gold standard. A doctor may also order a computed tomography (CT) scan if you can’t undergo MRI. Under imaging, glioblastoma often crosses the midline of your brain and has a butterfly appearance.

Doctors can confirm that your tumor is glioblastoma with a tissue sample called a biopsy. The biopsy may be taken with a long needle if the tumor is easily accessible or during surgery to remove the tumor. Your doctor will test this tissue sample for cancer and certain gene mutations that might guide treatment decisions.

Current standard treatment for glioblastoma involves surgically removing as much of the tumor as safely possible. This procedure is called maximal resection. It may help relieve pressure on your brain and increase your overall survival.

Most people undergo chemotherapy and radiation therapy after surgery.

The National Comprehensive Cancer Network (NCCN) guidelines consider three factors in determining what types of chemotherapy and radiation therapy to administer:

  • whether you’re under or over the age of 70
  • whether your Karnofsky Performance Scale (KPS) is under or over 60. KPS is a measurement of how well you can undergo your daily activities.
  • methylation status of the MGMT gene, a genetic factor linked to better survival

The NCCN treatment recommendations are:

FactorsNCCN-recommended treatment
Age under 70
KPS above 60
Concurrent radiation therapy and chemotherapy with temozolomide with or without alternating electrical field therapy
Age under 70
KPS under 60
Hypofractionated radiation therapy with or without temozolomide at the same time or after radiation therapy
Age over 70
KPS above 60
Methylated MGMT
Hypofrractionated radiation therapy with temozolomide at the same time or after radiation therapy
Age over 70
KPS above 60
Unmethylated MGMT
Concurrent radiation therapy and chemotherapy with concurrent and adjuvant temozolomide as well as alternating electrical field therapy
Age over 70
KPS under 60
Hypofractionated radiation therapy alone

Researchers are continuing to examine new treatment options such as:

  • direct drug delivery to the tumor through a catheter
  • peptide vaccines and cell-based vaccines
  • targeted therapy drugs such as tyrosine kinase inhibitors
  • X-ray to increase the effect of radiation
  • immunotherapy

Is glioblastoma ever curable?

Glioblastoma is considered incurable, but researchers are examining many new treatments. Although it happens extremely rarely, some people can live for a long time. Cases of people living longer than 20 years have been reported.

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People with glioblastoma generally have very poor outlooks. It’s one of the most aggressive types of cancer that develops in your brain or spinal cord.

  • About half of people with glioblastoma live less than 15 months.
  • Only about 5.5% of people live more than 5 years.
  • Only 3% to 5% of people live more than 3 years.
  • Less than 1% of people live at least 10 years.

Mutations in the IDH1 and lDH2 genes as well as MGMT (methylated) are associated with a better response to treatment. Decreased expression of some of other genes such as CHI3LI and FBLN4 are also associated with better survival.

Glioblastoma is a rare but aggressive type of cancer. It can develop in your brain or spinal cord, but almost all cases occur in the brain.

Only a small number of people with glioblastoma live longer than 5 years, but researchers are continuing to examine how to best treat it. Although rare, there have been case studies reporting people living for 20 years or longer.