Exercise slashes the risk of death in patients with colon cancer by more than a third, a trial has found.
Physical activity could also prevent the disease from coming back, as well as lifting mood, reducing fatigue and boosting strength, according to researchers.
Colon cancer develops in the part of the large intestine known as the colon, part of the large bowel, which also comprises the rectum and anus.
It can sometimes be referred to as bowel cancer or colorectal cancer.
The CO21 Challenge trial, led by researchers in Northern Ireland and Canada, involved 889 people with colon cancer from six countries.
All patients had had surgery and chemotherapy for their cancer and were deemed well enough to exercise, but were not meeting recommended physical activity levels.
Around half were given a three-year tailored exercise programme, which included the likes of brisk walking, circuit classes, cycling, or swimming.
The plan included in-person coaching sessions for the first six months, as well as regular meetings with a physical activity consultant.
The other group were offered materials that promoted exercise and nutrition.
The study found that after five years, the risk of dying, relapse or developing a new cancer was 28% lower in the group with a tailored exercise plan.
After eight years, patients in the physical activity group had a 37% lower risk of death.
Professor Vicky Coyle, UK lead researcher for the trial and clinical professor at Queen’s University Belfast, said: “During the trial, we supported people to reach their weekly exercise target in a way that worked for them.
“This could be a brisk walk for around 40 minutes every day, but some patients were also doing circuit classes, cycling, swimming, and many other activities.
“Our study gives clear, encouraging evidence that physical activity can reduce the risk of cancer returning for some people with colon cancer.
“We now need to work with policymakers and healthcare providers to embed exercise into treatment plans where appropriate.”
Dr Joe Henson, associate professor in lifestyle medicine at the University of Leicester, said: “Leading the exercise sessions in Leicester, I saw first-hand that this reduced fatigue, lifted people’s mood, and boosted their physical strength.
“We know that physical activity regulates several key biological processes that could explain these results, and further research will help us uncover why exercise is having such a positive impact.”
The findings, published in the New England Journal of Medicine and presented at the American Society of Clinical Oncology (ASCO), could “transform clinical practice”, according to experts.
Caroline Geraghty, senior specialist information nurse at Cancer Research UK, said: “Being active has many benefits, and this study shows that exercise doesn’t only improve well-being – it can also boost people’s chances of surviving colon cancer.
“Everyone recovering from cancer should have access to tailored support to help them live longer, better lives.
“This trial has the potential to transform clinical practice, but only if health services have the necessary funding and staff to make it a reality for patients.
“It’s important to remember that every cancer journey is different – starting new activities after treatment can feel overwhelming, and it may not be the right option for everyone. Take things at your own pace and speak to your doctor to discuss what is safe for you.”
Professor Peter Johnson, NHS national clinical director for cancer, said: “These exciting findings add to the growing evidence of the benefits of physical activity for people affected by cancer, not just in helping them be fitter for treatment and boosting their immediate recovery, but reducing the risk of the disease coming back.
“This is why we’ve asked cancer alliances across the country to look at ways to encourage and support patients to do physical activity and ensure every healthcare professional they see can help them be in the best possible place – both physically and mentally – before, during and after treatment.”
