Civil rights icon and Democratic Congressman John Lewis of Georgia revealed Sunday that he is battling stage four pancreatic cancer.

“I have been in some kind of fight — for freedom, equality, basic human rights — for nearly my entire life,’’ Lewis, 79, said in a statement. “I have never faced a fight quite like the one I have now.’’

Lewis — the last survivor of the Big Six group of civil rights activists led by the Rev. Martin Luther King Jr. in the 1960s — said he would continue to serve in office while undergoing treatment. Stage four cancer is the most advanced.

The Atlanta political stalwart said doctors discovered signs of the disease during a routine health check-up last month and that follow-up tests confirmed the diagnosis.

He said he is “clear-eyed about the prognosis’’ and that doctors told him “treatment options are no longer as debilitating as they once were, and that I now have a fighting chance.’’

Lewis added that he would be undergoing treatment for the next few weeks, although he did not say what kind.

“I may miss a few votes during this period, but with God’s grace, I will be back on the front lines soon,” Lewis said.

The US rep — who has been called “the conscience of Congress’’ — helped organize the 1963 civil rights March on Washington and delivered an address to the crowd right before King’s famous “I have a dream’’ speech.

He received a Presidential Medal of Freedom, the nation’s highest civilian honor, from President Barack Obama in 2011.

With AP