John McCain
John McCainReuters

US Senator John McCain (R-Ariz) said that he has been given a “very poor prognosis” by his doctors in his fight against brain cancer.

The 80-year old senator was diagnosed in July with primary glioblastoma, one of the most aggressive forms of brain cancer. He underwent surgery to remove the tumor.

The late Senator Edward M. Kennedy passed away from the same disease in 2009.

McCain told CBS' 60 Minutes in an interview which was aired Sunday that he often thinks about Senator Kennedy. He said he was inspired by how Kennedy “never gave up because he loved the engagement.”

McCain said that he sometimes experiences "fear of what happens,” but that he also has gratitude for having “had a great life.”

“It’s not that you’re leaving, it’s that you stayed,” he said.