RED WING — A 70-year-old endurance athlete from eastern Minnesota has written a book about his battle with melanoma and love of competing in marathons.

Dave Asp of Red Wing has been fighting cancer since May 2014, the Post Bulletin reported. He’s continued to compete during his treatment while also writing a book about his cancer experience and creating a melanoma support group at Mayo Clinic.

Asp has completed 27 American Birkebeiner cross country skiing competitions, 16 marathons, four Half Ironman and three Ironman competitions. He compares his cancer diagnosis to the sport.

“This was just going to be a 5K run — they’d go in and surgically remove the spot,” Asp said. “When it metastasized, then it turned into a marathon.”

Fighting cancer and preparing for a marathon require many similar traits including fortitude, resiliency, support of others and faith, Asp said. He said he hopes the book will inspire people, give them hope and build up their strength to push through any challenge.

“It’s not a self-help book or a how to, but hopefully people can glean from this what they can do and identify their own strengths,” Asp said. “If they have a big challenge ahead, they shouldn’t run from it. Take it on.”

Asp plans to donate the proceeds of the book, titled “Start Line and Beyond: Chronicles of an Athlete/Cancer Patient,” to the Mayo Melanoma Research Program.