BUFFALO, N.Y. -- Wednesday night, the office of Arizona Senator John McCain released a statement saying he has been diagnosed with brain cancer.

2 On Your Side spoke with the Chair of the Department of Neurosurgery at Roswell Park about this type of tumor and what lies ahead for the senator.

"This is a highly aggressive cancer of the brain that invades the normal tissue and is very difficult to cure, ultimately," said Robert Fenstermaker, MD.

He also said: "On average, people with glioblastoma survive about 15 months. It's possible to survive longer with aggressive treatment."

McCain and his family are currently reviewing treatment options, according to a statement.