Last week McCain underwent a procedure at the Mayo Clinic Hospital in Phoenix to remove a blood clot above his eye. During the procedure, doctors discovered a brain tumour (known as a glioblastoma). According to the American Brain Tumour Association, glioblastoma is an especially malignant tumour that forms in the tissue of the brain and spinal cord.
“The senator’s doctors say he is recovering from his surgery ‘amazingly well’ and his underlying health is excellent,” the statement read.
McCain may undergo chemotherapy and radiation for treatment, according to his office. He's currently recovering at home in Arizona as further treatment options are explored.
The Senator and 2008 Republican presidential nominee, 80, was reelected to his senate seat last November. McCain, who chairs the Senate Armed Services Committee, announced over the weekend that he would be unable to attend a health care vote due to medical treatment. However, the seriousness of his condition was unknown until today.
"John McCain is an American hero & one of the bravest fighters I've ever known. Cancer doesn't know what it's up against. Give it hell, John," Barack Obama wrote on Twitter.
During the Vietnam War, McCain was shot down, seriously injured, and captured by the North Vietnamese. Because he's the son of an admiral, McCain was offered an out-of-sequence early repatriation offer, which he refused. "I just didn't think it was the honourable thing to do," he said, referring to the standard practice of prisoners being released in the order they were captured.
McCain spent over five years as a prisoner of war. After retiring from the Navy in 1981, he moved to Arizona and entered politics. He was elected to the House of Representatives in 1982, and was first elected to the Senate in 1986.
President Trump has yet to comment on McCain's diagnosis.