Glioblastoma is a type of very aggressive brain tumor. It is also known as glioblastoma multiforme.

Glioblastoma is one of a group of tumors called astrocytomas. These tumors start in astrocytes — star-shaped cells that nourish and support nerve cells (neurons) in your brain. However, a glioblastoma can contain many different types of brain cells — including dead brain cells. About 12 to 15 percent of people with brain tumors have glioblastomas.

This type of tumor grows very fast inside the brain. Its cells copy themselves quickly, and it has a lot of blood vessels to feed it. However, it rarely spreads to other parts of the body.

Glioblastomas are sometimes called grade 4 astrocytoma tumors. Tumors are graded on a scale from 1 to 4 based on how different they look from normal cells. The grade indicates how fast the tumor is likely to grow and spread.

A grade 4 tumor is the most aggressive and fastest-growing type. It can spread throughout your brain very quickly.

There are two types of glioblastoma:

  • Primary (de novo) is the most common type of glioblastoma. It’s also the most aggressive form.
  • Secondary glioblastoma is less common and slower growing. It usually starts from a lower-grade, less aggressive astrocytoma. Secondary glioblastoma affects about 10 percent of people with this type of brain cancer. Most people who get this form of cancer are age 45 or younger.

Glioblastomas often grow in the frontal and temporal lobes of the brain. They can also be found in the brain stem, cerebellum, other parts of the brain, and the spinal cord.

The median survival time with glioblastoma is 15 to 16 months in people who get surgery, chemotherapy, and radiation treatment. Median means half of all patients with this tumor survive to this length of time.

Everyone with glioblastoma is different. Some people don’t survive as long. Other people may survive up to five years or more, although it’s rare.

In children

Children with higher-grade tumors tend to survive longer than adults. About 25 percent of kids who have this tumor live for five years or more.

Extending life expectancy

New treatments are extending life expectancy even more. People whose tumors have a favorable genetic marker called MGMT methylation have better survival rates.

MGMT is a gene that repairs damaged cells. When chemotherapy kills glioblastoma cells, MGMT fixes them. MGMT methylation prevents this repair and ensures that more tumor cells are killed.

Glioblastoma can be hard to treat. It grows quickly, and it has finger-like projections into the normal brain that are hard to remove with surgery. These tumors also contain many different types of cells. Some treatments may work well on some cells, but not on others.

Treatment for glioblastoma usually involves:

  • surgery to remove as much of the tumor as possible
  • radiation to kill any cancer cells that were left behind after surgery
  • chemotherapy with the drug temozolomide (Temodar)

Other drugs that may be used to treat this cancer include:

  • bevacizumab (Avastin)
  • polifeprosan 20 with carmustine implant (Gliadel)
  • lomustine (Ceenu)

New treatments for glioblastoma are being tested in clinical trials. These treatments include:

  • immunotherapy — using your body’s immune system to kill cancer cells
  • gene therapy — fixing defective genes to treat cancer
  • stem cell therapy — using early cells called stem cells to treat cancer
  • vaccine therapy — strengthening your body’s immune system to fight off cancer
  • personalized medicine — also called targeted therapy

If these and other treatments are approved, they could one day improve the outlook for people with glioblastoma.

Doctors don’t know what causes glioblastoma. Like other cancers, it starts when cells begin to grow uncontrollably and form tumors. This cell growth may have something to do with gene changes.

You’re more likely to get this type of tumor if you’re:

  • male
  • over age 50
  • of European or Asian heritage

Glioblastoma causes symptoms when it presses on parts of your brain. If the tumor isn’t very large, you might not have any symptoms. Which symptoms you have depends on where in your brain the tumor is located.

Symptoms can include:

  • headaches
  • nausea and vomiting
  • sleepiness
  • weakness on one side of your body
  • memory loss
  • problems with speech and language
  • personality and mood changes
  • muscle weakness
  • double vision or blurred vision
  • loss of appetite
  • seizures

Keep reading: Other types of brain tumors and their risk factors »