Jennings Vows To Fight Lung Cancer

Veteran ABC News Anchor To Begin Chemotherapy Next Week

(CBS/AP)  Elizabeth Vargas subbed for Jennings on "World News Tonight" on Tuesday. She and Charles Gibson, who is in Rome for coverage of the pope's funeral, will spell him regularly, ABC News President David Westin said.

"He's already bringing to this new challenge the courage and strength we've seen so often in his reporting from the field and in anchoring ABC News," Westin told ABC staffers. "I know that all of us will give him every bit of support that he needs and asks for."

While still in his 20s, Jennings anchored ABC's evening news for two years in the 1960s. He returned to the desk in 1978 when third-place ABC tried a multi-anchor format, which was abandoned in 1983 when Frank Reynolds died from cancer. Jennings has been ABC's sole evening anchor ever since.

A Canadian who proudly became a U.S. citizen in 2003, the urbane Jennings dominated the ratings from the late 1980s to the mid-'90s, when Brokaw surpassed him.

Lately, Jennings has been inching up in the ratings against Brokaw's replacement, Brian Williams, who sent along best wishes on Tuesday. "Peter is a friend and the best of competitors," Williams said. "It will take more than this to scare the man I know."

Senay said all long-time smokers should consult with their doctors about the possibility of lung cancer.

"If you have symptoms such as infections that don't go away, shortness of breath, chest pain when you take a deep breath, if you're coughing up blood, or generalized things such as fatigue or weight loss, and you have a history of smoking, these are all good reasons to check it out with your doctor," she said.