Sen. John McCain (R-Ariz.), battling brain cancer, reflected on a life well lived in an emotional interview Sunday, saying he was “very happy” with his 81 years so far and noting, “Every life has to end, one way or another.”

Speaking to Jake Tapper on CNN's “State of the Union,” McCain offered an optimistic update on his health — “the prognosis is pretty good” — and acknowledged the challenges he's facing. “Look, this is a very vicious form of cancer that I'm facing, but all the results so far are excellent,” he said.

McCain gave shout-outs to the doctors overseeing his treatment, in particular the Mayo Clinic and the National Institutes of Health, and presented himself as a man at peace.

“I'm very happy with my life, I'm very happy with what I have been able to do,” he said. “And there's two ways of looking at these things. And one of them is to celebrate. I am able to celebrate a wonderful life, and I will be grateful for additional time that I have.”

McCain recounted some of his favorite memories, including his 2000 presidential campaign, which Tapper covered as a reporter — “We were the underdogs, we were fighting our way up,” he said — and bantered back and forth with Tapper, just as he has done with generations of journalists.

When Tapper said he hoped it was not his last interview with McCain, the senior senator from Arizona quipped, “A lot of people want it to be the last.”

Tapper then asked him a final question: How does McCain want the American people to remember him?

“He served his country,” McCain said. “And not always right. Made a lot of mistakes. Made a lot of errors, but served his country.”

Then he said, “I hope we could add 'honorably.'”

That, Tapper said, would not be a problem. “I think that we can say 'honorably,'" the host concluded.