What is glioblastoma?

Sen. John McCain (R-Arizona) died Saturday, Aug. 25 after a short battle with an aggressive form of brain cancer called glioblastoma.

McCain was diagnosed with cancer in the summer of 2017 following surgery to remove a blood clot from behind his eye.

Here’s a look at the type of cancer McCain has.

What type of cancer is it?

McCain was diagnosed with primary glioblastoma, a type of brain tumor. Primary glioblastoma means the cancer started in the brain.

What is glioblastoma?

Glioblastoma forms in the tissue of the brain and the spinal cord. It is a very aggressive form of cancer.

What are the symptoms?

According to the Mayo Clinic, these are the symptoms of glioblastoma:

Nausea or vomiting
Confusion or a decline in brain function
Memory loss
Personality changes or irritability
Difficulty with balance
Urinary incontinence
Vision problems, such as blurred vision, double vision or loss of peripheral vision
Speech difficulties
Seizures, especially in someone without a history of seizures

Are there risk factors?

The Mayo Clinic lists these factors.

Age: Gliomas are generally diagnosed in people between the ages of 60 and 80, though it can occur at any age. McCain is in his early 80s.

Radiation exposure: Those who have been exposed to ionizing radiation have an increased risk of brain cancer. Ionizing radiation is the type of radiation used to treat cancer. It is also the type of radiation that is caused by the explosion of an atomic bomb.

Family history: Family history of brain cancer can increase the chances of contracting the disease.

How bad is the cancer? What is the prognosis?

Glioblastoma is a particularly aggressive form of cancer, according to the American Brain Tumor Association. The prognosis is often poor. The average survival rate for patients with malignant glioblastoma tends to be around 14 months with treatment. Around 10 percent of patients with the disease live five years or longer.

McCain is in very good health, according to his doctors. Prior to his diagnosis, he has not had problems with balance, headaches or seizures, according to a CNN story.

Did they get all of the tumor?

According to the CNN story, McCain's doctors said the tissue in which the cancer was found had been completely removed. However, glioblastomas often return.