Arizona Senator John McCain’s recent surgery for a blood clot above his left eye revealed that he has glioblastoma, an aggressive form of brain cancer.
What is glioblastoma?
Glioblastoma is the most common malignant (cancerous) brain tumor that makes up about 15.4 percent of all primary brain tumors, according to the American Brain Tumor Association. The ABTA estimates that there will be over 12,000 cases diagnosed by the end of 2017.
No one knows what causes glioblastoma, but tumors start in the brain or spinal cord and come from astrocytes, or star-shaped brain cells. There are two main types of glioblastoma tumors: primary (or de novo) and secondary. The primary tumors are the most aggressive and are recognizable quickly, while the the secondary tumors grow more slowly and are typically found in people under 45.
The most common symptoms of glioblastoma include headache, nausea, vomiting and drowsiness caused by increased pressure from the rapidly-growing tumors. Other symptoms include vision and memory problems, along with weakness on one side of the body and memory problems.
Glioblastoma treatment is difficult because the tumors are comprised of many different types of cells that respond differently to different treatments. Surgery to remove the malignant tumor is often necessary, but difficult, because of the tumors “finger-like tentacles,” according to the ABTA. A combination of treatments, including radiation and chemotherapy, are used to both remove additional parts of the tumor and keep it from spreading.
John McCain’s glioblastoma prognosis
Glioblastoma is considered a “median survival” cancer, meaning that an equal number of patients get better or worse with treatment. Glioblastoma life expectancy can range from 14 months to two or three years, depending on the type of glioblastoma, but 10 percent live five or more years after diagnosis, according to the ABTA.
Both Senator Edward Kennedy and former Vice President Joe Biden’s son, Beau Biden, died from glioblastoma. McCain’s doctors aren’t speaking on his own prognosis, though.
"Further consultations with Senator McCain's Mayo Clinic care team will indicate when he will return to the United States Senate," McCain's office said in its statement Wednesday.
But McCain is a fighter, according to his colleagues.
“He’s a warrior," Republican Senator John Thune told CBS News' CBS This Morning program. "I’ve seen him work guys half his age into the ground. He’s a remarkable individual.”
"Trust me, John's in fighting shape,” Massachusetts Senator Elizabeth Warren added in a tweet.