Seven-time Tour de France winner and cancer survivor Lance Armstrong is calling on Congress to renew the nation's war on cancer.

"It's time for our country to refocus and relaunch a comprehensive war on this disease," Armstrong said Thursday.

America's aging population and younger people who are less physically active than they should be make it more urgent than ever to find better ways to combat cancer, Armstrong said.

"This opponent is probably tougher than anything we'll ever face," he said.

Armstrong, who lives in Austin, Texas, and was raised in the Dallas area, was diagnosed in 1996 with testicular cancer that spread to his lungs and brain. But he recovered to win the world's premier cycling event from 1999 to 2005. The Lance Armstrong Foundation supports cancer research, prevention and better care for cancer survivors.

"For me, this is not a cause that I picked," he said. "It picked me."

Armstrong appeared before a Senate panel with Elizabeth Edwards, the wife of former Sen. John Edwards, the 2004 Democratic vice presidential nominee. Even after she was diagnosed with cancer and went through chemotherapy following the 2004 election, the couple continued public activities and she wrote a memoir.

After her cancer returned in early 2007, her husband remained in the 2008 presidential race and she continued to campaign for him before he dropped out. She works on health care policy at a Washington think tank.

Armstrong said he backs legislation sponsored by Sen. Edward Kennedy, D-Mass., and Sen. Kay Bailey Hutchison, R-Texas, to create a more comprehensive approach to fighting cancer.

The measure seeks to improve the coordination of cancer research, prevention and treatment while giving more money to the National Cancer Institute and other public research agencies.

"We think the American people want action - and they deserve action," said Kennedy. "It's a complex disease and it requires comprehensive strategies to fight it."