LEWISTON, Maine (AP) — Thousands of runners took part Saturday in the sixth Dempsey Challenge, the first time the cancer support fundraiser in honor of Patrick Dempsey's mother has been held since her death.

"This year's Dempsey Challenge is difficult without our mother but she is with us in our hearts and minds," Dempsey and his sisters, Mary and Alicia, said in a statement. We are reminded of her strength in all of the survivors, friends, patients and family who join us this weekend in celebrating hope."

For five years, their mother Amanda Dempsey led the survivor walk that opened the event. She was diagnosed with ovarian cancer in 1997 and battled multiple recurrences in the years that followed. She died in March at 79.

Patrick Dempsey, who plays Dr. Derek Shepherd on TV's "Grey's Anatomy," launched the Dempsey Challenge because of his mother's battles.

Money raised from the event goes to The Patrick Dempsey Center for Cancer Hope & Healing, which he and his sisters created in 2008 in partnership with the Central Maine Medical Center in Lewiston. Last year's Dempsey Challenge raised $1.1 million for the center, which provides free support, education and integrative medicine services for anyone impacted by cancer.

Saturday's events included 5K and 10K runs. Sunday's events focused on cycling, with rides ranging from 10 miles to 100 miles, following by a closing ceremony with the actor.