COLORADO SPRINGS, Colo. -- The U.S. Anti-Doping Agency stripped Lance Armstrong's seven Tour de France titles Friday, erasing one of the most incredible achievements in sports after deciding he had used performance-enhancing drugs to do it.

Armstrong, who retired a year ago, was also hit with a lifetime ban from cycling. An athlete who became a hero to thousands for overcoming cancer and for his foundation's fight against the disease is now officially a drug cheat in the eyes of his nation's doping agency.

In a news release, USADA said Armstrong's decision not to take the charges against him to arbitration triggers the lifetime ineligibility and forfeiture of all results from Aug. 1, 1998, through the present, which would include the Tour de France titles he won from 1999 through 2005.

Armstrong has strongly denied doping and contends USADA was on a "witch hunt" without any physical evidence against him.