Danni Duncan Beat Bowel Cancer. A Year Later, She Ran New York.

Somewhere past 30 kilometres on Sunday, Danni Duncan’s legs were spent. She kept going. She crossed the finish line of the New York City Marathon in Central Park in 3 hours, 35 minutes and 27 seconds, and posted the time that night with four lines underneath it: 12 months cancer free. 4 kids. Over 40. On my period. “I am so frickin proud of myself,” she wrote. “I did a really hard thing for all those who can’t.”

A year and a half earlier, the Australian women’s health and fitness coach had been told she had bowel cancer. She was 39, seven months on from the birth of her fourth child, and by her own description the healthiest person she knew. New York had been the dream before any of it. “2025 the year I turned 40 my dream was to run New York,” she wrote on race day. “But cancer had other plans. Little did it realise who it was dealing with.”

The diagnosis: The tiredness that wasn’t normal for her

Duncan had lived with an IBS diagnosis since she was 11, so changes in her gut were easy to file under the old explanation. What did not fit was the tiredness. As a new mother of four she was “unusually fatigued,” struggling through runs and workouts, dizzy, bloated in a way that felt new. Her iron had run low through the pregnancy. When the tests came back she was so anaemic, she told LADbible, that her doctor said she should have been bleeding out in front of her. Her husband, Chris, pushed her to get checked.

On May 15, 2025, a colonoscopy found a tumour of 2.7 centimetres, LADbible reported. It was stage 2. She was, she said, “the freaking healthiest person” she knew.

The treatment: Surgery, four rounds of chemo, and back to training

Two weeks later surgeons performed a right hemicolectomy, removing 25 centimetres of her bowel along with 17 lymph nodes, the Jodi Lee Foundation says. Four rounds of chemotherapy followed, and with them the news that she could no longer breastfeed her baby. She trained through it: she was working out ten days after the operation and running two weeks after it.

In November 2025, follow-up scans and a colonoscopy showed no evidence of cancer, SurvivorNet reported. She now has a CT scan every year and a colonoscopy every two years.

New York: Two personal bests, one finish line

She did not run it alone. Chris, who had 20 percent of his lung removed in 2024, in his own words on their fundraising page, has become a marathoner beside her. After the Gold Coast Marathon in July she wrote: “Chris is not a runner. But last weekend he ran 42.195 kilometres anyway.” In New York, they both set personal bests. “But bloody hell, New York made us work for them,” she wrote in her race debrief. “I’m so bloody proud of us.”

They ran for the Jodi Lee Bowel Cancer Foundation, an Australian charity founded in 2010 after Jodi Lee, diagnosed with bowel cancer at 39, died a few days before her 42nd birthday. Its mission is “to empower everyone to take active steps to lead longer, healthier lives free from bowel cancer,” and Duncan is one of its ambassadors. Their fundraiser passed its goal before the start gun, and it is still open.

The signs: What she tells people not to ignore

Duncan now uses her platform to talk about the signs she put down to something else. She names three. Fatigue that isn’t normal for you: “This wasn’t your normal ‘I need a nap’ tired,” she said. Bloating you can’t explain. And your gut instinct, the sense that something is off. “Your gut is your second brain,” she told LADbible. “Listen to it.” Blood in the stool and a change in bowel habits are the better-known signs, and she lists those too.

Her other line is about age. “This is no longer an old person’s disease,” she told the foundation. In the United States, American Cancer Society figures show colorectal cancer among adults aged 20 to 49 rising about 3 percent a year from 2013 to 2022, as we reported in October. Her advice is the same as the foundation’s: if something is off for you, get checked, and if you are not being heard, get a second opinion.

Where this comes from: Sources

Danni Duncan’s words are from her Instagram posts of November 1 and 2, 2026, which are embedded above, from her Substack debriefs of the New York and Gold Coast marathons, and from her Jodi Lee Foundation ambassador page. Her diagnosis and treatment are as reported by LADbible (June 18 and October 6, 2026) and SurvivorNet (September 13, 2026). Chris Duncan’s words are from their fundraising page, and the foundation’s history is from its own site. The finish time and the personal bests are as she posted them. The illustration is ours. This article is educational, describes what the cited sources say, and is not medical advice.