Lance Armstrong introduced himself as a seven-time Tour de France champion at a cancer conference today.

"My name is Lance Armstrong. I am a cancer survivor," he said to open his speech to the World Cancer Congress. "I'm a father of five. And yes, I won the Tour de France seven times."

Armstrong announced last week he would no longer challenge the US Anti-Doping Agency's drug charges against him. USADA threw out his competitive victories dating to 1998, which would include all seven Tour wins.

Armstrong, who has maintained his innocence, focused on his experience as a cancer survivor and the work of his charitable foundation.

He said he struggled to get enough information following his diagnosis in 1996.

"After I left the doctor's office, I was grabbing every pamphlet and flyer I could off the wall," he said. "You know what we did after that? We went to the bookstore - remember those things."

Armstrong also announced his foundation would donate an additional $US500,000 ($NZ625,000) to a joint initiative aimed at increasing access to cancer care around the world.

Armstrong briefly returned to the doping scandal at the end of his remarks, vowing it wouldn't impact his charitable work.

"I think the real issue here is one of distraction," he said. "I'm going to tell this to you all as if you're friends and partners and allies. I'm not going to be distracted from this fight."

Later, hundreds of people joined Armstrong on an hour-long training run up Mount Royal. The runners cheered and tried to pose for photos with Armstrong when he arrived at a park.

- AP