What to Know About Glioblastomas

Allison Bush | Apr 7th 2015

Reviewed by Todd Gersten, MD

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What are glioblastomas?

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According to the American Brain Tumor Association, glioblastomas (GBM) are tumors that arise from astrocytes, which are the star-shaped cells that make up the supportive tissue of the brain. These tumors are usually highly malignant (cancerous) because the cells reproduce quickly and they are supported by a large network of blood vessels.

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Where are they located?

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Glioblastomas are generally found in the cerebral hemispheres of the brain, but can be found anywhere in the brain or spinal cord.

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What are the symptoms?

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Because glioblastomas can grow rapidly, the most common symptoms are usually caused by increased pressure in the brain. These symptoms can include headache, nausea, vomiting, and drowsiness. Depending on the location of the tumor, patients can develop a variety of other symptoms such as weakness on one side of the body, memory and/or speech difficulties, and visual changes.

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Are glioblastomas common?

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This particular tumor represents about 17 percent of all primary brain tumors and about 60-75 percent of all astrocytomas. They increase in frequency with age, and affect more men than women. Only three percent of childhood brain tumors are glioblastomas.

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How do you treat glioblastomas?

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The first step in treating glioblastoma is a procedure to make a diagnosis, relieve pressure on the brain, and safely remove as much tumor as possible through surgery. Because glioblastomas have finger-like tentacles, they are very difficult to completely remove.

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What causes glioblastomas?

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Unfortunately, the exact cause of glioblastoma is unknown.

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What's the prognosis?

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The American Brain Tumor Association notes that prognosis is usually reported in years of “median survival.” For glioblastoma, treated with concurrent temozolamide and radiation therapy, median survival is about 14.6 months and two-year survival is 30 percent. However, a 2009 study reported that almost 10 percent of patients with glioblastoma may live five years or longer.