What is glioblastoma?

glioblastoma 1
What is glioblastoma?
01:13 - Source: CNN
CNN  — 

Sen. John McCain died Saturday, more than a year after he was diagnosed with glioblastoma, an aggressive brain tumor.

On Friday, his family said in a statement that McCain had made the decision to discontinue medical treatment.

Unlike other brain tumors that start in the body and spread to the brain, glioblastoma starts in the brain or spinal cord. The tumor arises from star-shaped brain cells known as”astrocytes.” The American Brain Tumor Association labels the tumor “highly malignant” and cancerous because of its ability to invade and stay within normal brain tissue.

The senator underwent surgery to remove a blood clot in July 2017 at the Mayo Clinic in Phoenix. Lab results from the surgery confirmed the presence of glioblastoma.

Glioblastoma is the most common of all malignant brain tumors, representing 15.4% of all primary brain tumors, according to the brain tumor group.

This form of tumor killed Sen. Ted Kennedy and Beau Biden, the son of former Vice President Joe Biden.

Glioblastoma symptoms

CNN Chief Medical Correspondent Dr. Sanjay Gupta spoke in 2017 to doctors involved in McCain’s care with permission from his family.

Gupta said he learned McCain had felt tired over the months before his diagnosis and had a bout of double vision but blamed it on his intense travel schedule.

Doctors ordered a CAT scan and an MRI scan of McCain’s brain that revealed the tumor.

The symptoms of glioblastoma are usually a result of increased pressure on the brain.

The American Brain Tumor Association lists headaches, nausea, vomiting and drowsiness as symptoms for the tumor. Depending on where the tumor is, however, weakness on one side of the body, memory and speech difficulties and visual changes can all be developed as a result.