Glioblastoma multiforme — the type of tumor that U.S. Sen. John McCain (R-Ariz.) has been diagnosed with — is an aggressive form of brain cancer that is rare and typically occurs in adults.

According to the American Brain Tumor Association, there are about 12,390 new cases a year in the U.S.

Go Ad-Free, Get Exclusive Shows and Content, Go Premium Today - $1 Trial

[lz_ndn video=32724081]

McCain had undergone surgery last week to remove a blood clot from above his left eye.

Doctors at the Mayo Clinic in Phoenix said the clot was an indicator that the tumor started to grow.

Patients with this aggressive form of cancer face a grim survival rate.

Quick - Do This Before Biden “Fixes” Your Retirement Plan Next …

About 4 percent of patients over age 55 live for five years.

McCain’s doctors managed to remove all of the tumor that was visible on the brain scans, but surgery is hardly ever enough. Glioblastomas plant microscopic roots that go deeper into the brain tissue, making the tumors aggressive and hard to target.

Who Is A Bigger Threat To America?

By completing the poll, you agree to receive emails from LifeZette, occasional offers from our partners and that you've read and agree to our privacy policy and legal statement.

Related: A Chewing Gum That Detects Cancer?

Standard treatment following surgery includes a combination of chemotherapy and radiation, which can take weeks to months.

Even among those who respond well to initial treatment, the cancer can come back, often within 12 to 24 months.

Related: Cancer Detection: Lighter, Quicker, Better

McCain is a long-term survivor of melanoma, but doctors classified this new cancer as a “primary tumor,” meaning it’s not related to his former malignancies.

This Fox News piece is used by permission; the Associated Press contributed.

Read more at Fox News:
U.K. McDonald’s, KFC, Burger King Drinks Test Positive for Poo Bacteria
Family Finds Catheter in Tub of Ice Cream, Requires Testing for Hepatitis, HIV
Tabasco Debuts Scorpion Sauce, Hottest One Yet

(photo credit, homepage image: Tdvorak, Wikimedia)