John McCain Was Diagnosed With A Glioblastoma, Among The Deadliest Of Cancers

"Doctors use words like 'aggressive' and 'highly malignant' to describe the type of brain cancer discovered in Arizona Sen. John McCain."

"The cancer is a glioblastoma, the Mayo Clinic said in a statement Wednesday. It was diagnosed after doctors surgically removed a blood clot from above McCain's left eye."

"Doctors who were not involved in his care say the procedure likely removed much of the tumor as well."

"Glioblastomas, which are the most common malignant brain tumor, tend to be deadly. Each year in the U.S., about 12,000 people are diagnosed with the tumor. Most die within two years, though some survive more than a decade."