Catherine Butschi of Cedar Rapids, one of about 70 students bicycling more than 4,000 miles to raise money for cancer research, stopped in Iowa City with her teammates Tuesday night. She wanted to talk with Iowans about cancer prevention.

Texas 4000, launched in 2004 by a pair of University of Texas students, is the longest annual charity ride in the world, according to the program website. Riders seek to uphold the program’s tenets of spreading hope, knowledge and charity in the fight against cancer along their route from Austin, Texas, to Anchorage, Alaska.

Butschi, who graduated this spring with a degree in accounting from the University of Texas, applied for the ride after a friend who completed the trek in 2015 told Butschi the experience was life-changing.

Riders have cycled more than 2,000 miles since they set out for Alaska about 30 days ago. They have raised more than $600,000 for cancer research and support and hosted educational programs about cancer prevention in communities along the way.

Their longest days require more than 100 miles of biking, Butschi said. Participants camp or sometimes stay in schools, churches and host homes along the route.

The cause makes the challenge of the past month well worth the effort, Butschi said.

“We meet these kids who are in hospitals ... and I’m sure they want to be outside on bikes all day, so we do it for them,” she said.

Teammate Riddhi Patodia, a medical student, will complete the 4,000-mile ride while applying to medical schools. She said thinking of her dad inspires her to keep cycling through mental and physical exhaustion. He is going through cancer treatment.