A 70-year-old man who spent last year battling stage 3 colorectal cancer is now preparing to run 26.2 miles through the streets of Washington, D.C. David Turner completed eight rounds of chemotherapy, developed nerve damage in his hands and feet along the way, and kept walking anyway — logging 650 miles on foot before deciding he was ready to toe the start line of the Marine Corps Marathon this month.
Turner was diagnosed with stage 3 colorectal cancer in June 2025, just months after he had already begun training for the very marathon he now plans to run, according to the Baltimore Sun. The former CEO of a glassware manufacturing company had lived an active lifestyle for years before the diagnosis interrupted his plans, and by September 2025 he had committed to staying active despite the mobility challenges his treatment brought on.
The chemotherapy side effects worsened as treatment went on, leaving Turner with neuropathy and pelvic pain that made movement painful. Yet he said walking made him feel strongest during chemotherapy, and he kept at it, frequently covering three to five miles at a stretch even as his body fought the cancer and the drugs meant to treat it.
Training Through Nerve Damage
Training Through Nerve Damage Peripheral neuropathy is a recognized complication of some cancer treatments. Chemotherapy-induced peripheral neuropathy affects more than half of patients undergoing neurotoxic treatment regimens, causing pain, numbness, and balance problems in the hands and feet, according to research indexed on PubMed. The condition can linger long after active treatment ends.
To manage it, Turner turned to REPS Performance in Severna Park, where coach Devin Conway built him a program of strength, core, and stamina training. Conway described Turner's progress as really impressive. That kind of targeted exercise work is more than anecdotal support — research published in JAMA Internal Medicine and detailed by ECancer found that targeted balance and physical exercise sessions during chemotherapy can reduce the incidence of peripheral neuropathy by 50% to 70%, with the activity believed to promote nerve neuroplasticity and reduce inflammation.
Turner's approach also lines up with where oncology guidance has moved in recent years. The American Cancer Society now advises cancer survivors to aim for 150 to 300 minutes of moderate-intensity exercise per week to help offset treatment side effects, a shift from the rest-focused advice oncologists once gave patients. Clinical guidelines from the American Society of Clinical Oncology, highlighted by UT MD Anderson, indicate that regular exercise during active chemotherapy reduces fatigue, anxiety, and loss of physical function, with recent trials also pointing to survival benefits from exercise after chemotherapy ends.
Racing Toward October 25
After finishing his eight chemotherapy sessions, Turner is now in a cancer surveillance period and has been rebuilding his endurance through a string of races. He ran the Baltimore Sole of the City 10K, the Annapolis 10-Miler in August 2026, and the Bar Harbor YMCA Half Marathon in Maine in September 2026, steadily working back toward marathon distance.
The Marine Corps Marathon itself is built for runners like him. The 51st running of the race is set for October 25, 2026, covering a 26.2-mile course that starts near the Pentagon in Arlington, Virginia, and finishes at the Marine Corps War Memorial, according to the race guide published by RunningLog. It is the largest marathon in the country that offers no cash prize money or elite appearance fees, maintaining a 7-hour finish window built for everyday participants rather than competitive racers — earning it the nickname the People's Marathon, with the Marine Corps organizing an event that typically draws around 30,000 runners.
That structure suits Turner's stated goal exactly. He does not aim to set a new personal record and has said he is not concerned about his marathon time at all. His goal, he said, is simply to reach the starting line.
A New Mission Beyond the Finish Line
Turner has turned his experience into something bigger than one race. He created walkingforapurpose.org, a project aimed at inspiring people to maintain an active lifestyle, and he has said he wants to be an example for people who think movement is out of reach for them.
His stage 3 diagnosis carries a five-year relative survival rate of approximately 73%, according to American Cancer Society figures cited by Honcology, with stage 3 meaning the cancer had spread to nearby lymph nodes but not to distant organs. Colorectal cancer is expected to be diagnosed in an estimated 158,850 people across the U.S. this year, making it the fourth most common cancer nationally and the second leading cause of cancer deaths, per the American Cancer Society. Incidence among adults 65 and older, Turner's age bracket, has actually been declining by about 2.5% annually in recent years, a trend linked to increased colonoscopy screening in that age group even as rates climb among younger adults.
Federal guidelines from the U.S. Preventive Services Task Force recommend routine colorectal cancer screening for all average-risk adults between ages 45 and 75, though roughly one in three eligible adults nationwide still goes unscreened. For Turner, now rebuilding mile by mile after chemotherapy, the marathon start line in Arlington later this month stands as its own kind of milestone — proof, in his telling, that movement remained possible even in the hardest stretch of treatment.
