WASHINGTON — Rep. Tom Lantos, a Democrat of California, a Holocaust survivor who became the highly regarded chairman of the House Foreign Affairs Committee, announced yesterday that he has cancer and will not run for re-election in November.

Mr. Lantos, who will turn 80 on February 1, said a routine medical test last month showed that he has cancer of the esophagus. The nature of the illness and the treatment it will require convinced him to retire at year’s end.

“It is only in the United States that a penniless survivor of the Holocaust and a fighter in the anti-Nazi underground could have received an education, raised a family, and had the privilege of serving the last three decades of his life as a member of Congress,” Mr. Lantos said in a statement. “I will never be able to express fully my profoundly felt gratitude to this great country.”

Elected in 1980, the Hungarian-born Californian has used his remarkable biography as much as his political stature to advance the cause of human rights and become one of Congress’s leading voices on foreign policy. Mr. Lantos was 16 when Nazi forces occupied his native Budapest and began rounding up Jews. He escaped a forced labor camp, only to be captured and beaten before escaping again to a safe house protected by a famed Swedish diplomat, Raoul Wallenberg.

During much of World War II, he moved about Budapest in a military cadet’s uniform, procuring food for other Jews in hiding. A 1947 scholarship brought him to America, where he earned a doctorate from the University of California at Berkeley, before settling in as an economics professor at San Francisco State University.

A champion of Israel as well as international human rights, Mr. Lantos has traveled from North Korea to Iraq to Syria. His sharp tongue has at times drawn rebukes from Republicans, but he worked closely for much of this decade with Henry Hyde, who chaired the committee before the Democratic electoral sweep of 2006.

Mr. Lantos helped craft the 2002 resolution that authorized war with Iraq, proclaiming: “Had the United States and its allies confronted Hitler earlier, had we acted sooner to stymie his evil designs, the 51 million lives needlessly lost during that war could have been saved.”

Since then, he has turned strongly against the Iraq War and the Bush administration’s prosecution of it, helping the House speaker, Rep. Nancy Pelosi, a Democrat of California, devise her so-far fruitless strategies to force a change of course.

“It is with great personal sadness and deep appreciation for his outstanding leadership that I learned of Chairman Lantos’ illness,” Mr. Pelosi said in a statement yesterday. “His experience, intelligence and compassion will be deeply missed.”

Mr. Lantos expects to remain a vigorous committee chairman throughout his final year, a spokesman said. He plans to chair hearings on Pakistan later this month and hopes to summon Secretary of State Rice before his committee within weeks to defend her budget request for 2009.