Bob Dole, the former senator and 1996 Republican presidential nominee, announced on Thursday that he had advanced lung cancer.

“Recently, I was diagnosed with stage four lung cancer,” Mr. Dole said in a statement. “My first treatment will begin on Monday. While I certainly have some hurdles ahead, I also know that I join millions of Americans who face significant health challenges of their own.”

Mr. Dole, 97, represented Kansas in the Senate for more than 25 years, including 11 years as the chamber’s Republican leader. He gave up his position as majority leader to run for the White House in 1996, only to lose to President Bill Clinton by a large margin, 379 electoral votes to 159.

He has faced health challenges for decades, starting with a battlefield injury during World War II, in which he served as an Army second lieutenant. He was hit by machine-gun fire, which almost killed him and permanently limited his use of his right arm. He went on to support the Americans with Disabilities Act, passed in 1990, and later pushed for the United States to join the United Nations Convention on the Rights of Persons With Disabilities.

Mr. Dole — the oldest living former presidential nominee or president, one year older than former President Jimmy Carter — disclosed his lung cancer diagnosis a day after the conservative talk radio host Rush Limbaugh died of the same disease.