PEABODY – Attempting a 50-mile bike ride can be a daunting task for your average healthy person, but for Peabody resident Tom DesFosses, it could mean life or death.DesFosses was diagnosed with primary CNS lymphoma, a cancerous brain tumor, more than four and a half years ago. The doctors deemed the tumor inoperable so he has been forced to survive with the help of frequent treatments of chemotherapy and a strong will to live.On Sunday, Sept. 7, DesFosses will prove his determination to beat the disease with “A Reason to Ride,” a bicycle ride along the North Shore to raise awareness and funds for cancer research at Beth Israel Deaconess Medical Center in Boston. More specifically, the proceeds will go to the Dr. Eric Wong?s Brain Tumor Research Fund and the Dr. Lewis Cantley?s General Cancer Research Fund.The ride will take bicyclists from the Liberty Tree Mall in Danvers through a scenic tour of Beverly, Wenham, Essex and Gloucester, before winding back to the starting point.?For me, this ride will be very emotional, but in another way, it will give me incredible joy,” wrote DesFosses on the ride?s Web site. “It will give me time to reflect on how blessed I am to be a cancer survivor, and to think of others who are not able to join me on this quest.”This won?t be the first ride for the 66-year-old, who last year made a solo 750-mile trip though the six New England States.?(This) is a lot harder than last year,” he said. “Back then I was only responsible for myself.”So far, approximately 50 people have signed up to ride, not exactly as many as DesFosses had in mind, but he?s not discouraged. He hopes his ride will be the start of a tradition, a fundraiser that will carry on for many years.?The longer the fight goes on, the easier it becomes, until you are convinced you are winning,” he wrote. “Once you know this, the cancer has lost the upper hand. All you need to do then is stay positive about your journey. I also know that even if cancer beats me in the end, I will have given it one hell of a fight. But it won?t! And I?m here today, riding my bike on another type of journey to prove it.”Riders will receive a free bike inspection, money-saving coupons to Ski Market, refreshments and food. There will also be plenty of activities for non-riders to participate in. They have a choice to complete a 50-, 25-, or 10- mile trip with varying start times. Helmets are necessary. For more information on how to ride or donate, log on to www.areasontoride.com.