Ontario man runs Boston Marathon while battling stage 4 cancer

One month after defying the odds and qualifying for his ninth Boston Marathon in September while battling stage 4 cholangiocarcinoma–the rarest of rare cancers–Dana Fox of Waterloo, Ont., received devastating news: his tumour was growing again.

Yet he refused to be stopped from returning to Boston, and after enduring two more months of gruelling chemotherapy, joining a clinical trial for a new drug and inspiring many along the way, the 66-year-old finished the 42.2K race in five hours and 36 minutes.

“It was an epic weekend,” Fox told Canadian Running. “Longest time on feet ever–I was careful to not go too far in the deep end. I just thought every step was for a family that wasn’t sure if they could make it to the finish line.”

The initial diagnosis

In October 2023, during a Sunday long run, Fox felt tingling in his fingers and shortness of breath. Within five days, he was diagnosed with cholangiocarcinoma, a very aggressive cancer that forms in the bile ducts. He was told he wouldn’t make it past October 2024.

He began chemo that December, continuing until May; immunotherapy, which assists the immune system with identifying and attacking cancer cells, continued until September 2024.

“As soon as you do chemo, you can’t run,” Fox said. “You keep getting weaker, you can’t make it up stairs, you’re just gassed.”

But when his son, Jordan, pointed out that “Chemo is an injury–athletes know how to recover from an injury,” Fox was more motivated than ever to beat his cancer. He brought his first pair of running shoes, gifted to him by his father in 1971, to every chemo “workout.”

The return to running

By January 2024, Fox had already lost 25 lb; he couldn’t even support himself on his bike. With lost body fat and muscle mass, he had to wear a winter hat and coat to stay warm while cycling. But he was determined to try running anyway–at first just making it down the driveway, then around the circle on his street. He joined a local race, the Arctic Mile, in February, running just the final 30 metres.

The day after finishing chemo in the spring, he raced a 5K, not knowing if he’d be able to finish–but came fourth in his age group. “Your body doesn’t want to quit,” he said. “Your body wants to live.” He continued to try running every day, but avoided speedwork and long runs.

The following weekend, Fox and his family took on the 200K Ride to Conquer Cancer, raising C$40,000. “You get to meet 5,000 other people affected by cancer,” he said. “You realize you’re not the only one.”

Qualifying for Boston

Fox still doesn’t know how he managed to qualify for the 2025 Boston Marathon. “It’s an interesting training program when you have cancer and are coming off chemo,” he said. “I did six long runs–I went from barely doing a 5K in June to running a marathon in September. And I didn’t just finish–I qualified for Boston. That doesn’t just happen.”

At the 2024 Georgina Marathon, Fox clocked 3:56:50, beating the cut-off time by more than a minute.

“If I followed their advice, I would have been a statistic”

In October 2024, when a CT scan showed his tumour was growing again, he decided he was sick of hearing the words “I’m so sorry, there’s nothing you can do.”

“I need a coach that tells me what I need to work on,” Fox said. He was referred to The Princess Margaret Cancer Centre in Toronto, where his new surgeon, Dr. Sean Cleary, asked him, “You look pretty fit, what’s the plan?”

After undergoing chemo for another two months, Fox entered into a clinical trial for a new drug, Tibsovo; he’s one of just 16 people in Canada in the trial. And so far, he’s faced zero side effects.

For his marathon build, he slowly increased the time he spent biking, and then running. He completed five long runs over five weeks–building from 10K to 30K by the end of March. “I’ve taken a detour in the middle, but I’m going to make it to the start line in Boston,” he said. “Will I get a PB? No. But I’ll be happy to make it to the start line and happy to make it to the finish line.”

Using his journey to spread hope

Fox’s cancer journey goes far beyond just his own personal treatment–he has built a community of hope. The athlete has spoken at cholangiocarcinoma conferences to connect with other survivors and cancer researchers. “They all want a little bit of hope–even if it’s to do something easier than a marathon,” Fox said. “If there’s one person who can stand up and say it was hard, but it wasn’t impossible, then that might give them the hope they need. You don’t have to see the finish line to keep moving forward.”

Fox has also made his own podcast, Running With Hope, and wrote a book, Surviving Cancer Marathon: Strategies for Cancer Recovery, Inspiration and Wellness. His newest endeavour is a documentary, set to premiere during Cancer Week in February 2026. “We’ve started filming already,” Fox said. “They spent a week in my house, and come to all my workouts and Sunday long runs.”

At one of his conferences, he met Sydney Towle, a 23-year-old runner with cholangiocarcinoma; he invited her to be part of the documentary, and the pair made plans to run next year’s New York City Marathon together as a fundraiser.

He’s also started building “learn how to run” program with local running stores for those undergoing cancer treatment. “The groups will meet once or twice week,” he said. “It will be a good incentive to get out of house, not be lonely and learn how to be mobile again.”

What’s next?

The Canadian M65-69 marathon record stands at 2:54–and Fox sees it as yet another challenge to conquer. “At the 2026 Berlin Marathon, if I’m aiming for sub-three, I might as well go after the record.”