Civil rights icon and US Democratic Rep John Lewis of Georgia has been diagnosed with stage 4 pancreatic cancer, his office announced Sunday. Photo: Internet Source

Lewis, 79, said he was diagnosed following a routine medical visit with subsequent tests that reconfirmed the diagnosis. The long-time Georgia congressman will undergo treatment for the cancer.

"I have been in some kind of fight -- for freedom, equality, basic human rights -- for nearly my entire life. I have never faced a fight quite like the one I have now," Lewis, who in March 1965 joined forces with Martin Luther King Jr. to lead a voting rights march out of Selma, Alabama, said in a statement.

He continued later: "While I am clear-eyed about the prognosis, doctors have told me that recent medical advances have made this type of cancer treatable in many cases, that treatment options are no longer as debilitating as they once were, and that I have a fighting chance."

Pancreatic cancer was the third-leading cause of death from cancer in the United States in 2018, after lung and colorectal cancers, according to the National Cancer Institute. The cancer, on average and across all stages, has a five-year survival rate of 9%, according to the American Cancer Society.