Lance Armstrong resigned as the chairman of Livestrong, his foundation dedicated to fighting cancer, in a statement issued Wednesday amidst mounting evidence that the award-winning cyclist used performance-enhancing drugs.

“To spare the foundation any negative effects as a result of controversy surrounding my cycling career, I will conclude my chairmanship,” Armstrong said.

On Oct. 10, the United States Anti-Doping Agency released a report outlining the drug use by Armstrong and 11 of his teammates when he won the Tour De France seven times from 1999 to 2005. In a statement accompanying the report, USADA CEO Travis Tygart said the team, which was sponsored by the U.S. Postal Service, created a “professionally designed” conspiracy to “groom and pressure athletes to use drugs, to evade detection, to ensure its secrecy and ultimately gain an unfair competitive advantage through superior doping practices.”

The report includes statements from 26 people, including 15 cyclists with knowledge of the team’s drug usage and documentary evidence including financial payments, emails and drug test results.

“The evidence shows beyond any doubt that the U.S. Postal Service Pro Cycling Team ran the most sophisticated, professionalized and successful doping program that sport has ever seen,” Tygart said.

Livestrong vice chairman Jeff Garvey will replace Armstrong as chairman, and Armstrong will remain on Livestrong’s 15-member board of directors, according to Armstrong’s statement.

Calls and emails to members of University of Texas Cycling, a student organization that is sponsored in part by Armstrong’s cycling store, Mellow Johnny’s Bike Shop, were not returned by press time.