LEWISTON — Actor Patrick Dempsey traded his race car for a bicycle this weekend at the Dempsey Challenge in his home state.

Dempsey returned to Maine for the two-day fundraiser involving biking, running and walking events after his racing team last week won the “Six Hours of Fuji” endurance race in Japan.

The event in Maine, where Dempsey was born, is a fundraiser for The Patrick Dempsey Center for Cancer Hope & Healing, which he and his sisters created in 2008 in partnership with Central Maine Medical Center in Lewiston. They were inspired by their mother, Amanda, who died from cancer last year.

Dempsey told the Sun Journal that coming home for the Dempsey Challenge is like coming home for a family reunion, sharing memories, grief, accomplishments and support. “The overall feeling and openness of everyone participating in the challenge is magical,” he said.

He was joined at the event’s annual Cancer Survivors’ Walk on Saturday by Joan Lunden, a television host who was diagnosed with breast cancer in 2014. On Sunday, Dempsey will be participating in a 50-mile ride.

Dempsey is best known as Dr. Derek Shepherd on TV’s “Grey’s Anatomy,” but he left the show earlier this year and put his focus on his racing team. He’s also filming the movie “Bridget Jones’s Baby” in London.

About 4,000 people were participating in the challenge, whose goal is to break the 2014 record of $1.41 million raised by 3,871 participants, officials said.