Arizona Sen. John McCain said battling brain cancer is a challenge but that his prognosis is "pretty good."

Speaking to CNN over the weekend, McCain admitted his recent brain cancer prognosis is tough on his family, but said he is confident he’ll get through it.

In his first week back at work in Washington, D.C., he told his fellow congressional members the United States needs to send a clear message to North Korea’s leader Kim Jong-un.

Responding to Kim’s testing of nuclear weapons he said it’s important the U.S. makes it clear the price for acting in an aggressive fashion “will be extinction.”

McCain serves as the Senate Armed Services chairman in congress. 

He is recommending the U.S. provide missile defense in South Korea and Japan, and work further with China to, “put the brakes on Kim Jong Un.”