New evidence has linked physical activity with improved colon health, underscoring the vital role of exercise in cancer prevention and care.
Author
- Justin Stebbing
Professor of Biomedical Sciences, Anglia Ruskin University
The landmark international trial - the Challenge study - showed that structured exercise programmes can dramatically improve survival rates for colon cancer survivors.
The study was unveiled at the meeting of the American Society of Clinical Oncology . Each June, cancer specialists from around the world convene in Chicago for the conference where new research is announced that pushes the boundaries of cancer treatment and this year's conference featured a wealth of exciting discoveries.
Conducted across six countries and published in the New England Journal of Medicine , the Challenge study tracked 889 patients for several years following chemotherapy. Participants were randomly assigned to one of two groups: one received standard post-treatment care, while the other took part in a three-year coaching programme that included personalised exercise plans and regular check-ins with fitness professionals.
The results were striking. Those in the exercise group experienced 28% fewer cancer recurrences and 37% fewer deaths.
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In the programme, people slowly built up how much they exercised, with most choosing to go on brisk 45-minute walks four times a week. Ninety per cent of the people who exercised stayed cancer free for five years, compared with just 74% of those who didn't.
This study provides the first strong evidence that exercise not only correlates with better outcomes but directly improves survival rates in cancer patients. While earlier observational studies found a link between being active and better cancer outcomes , this first randomised controlled trial helps show causation, meaning that exercise can directly benefit the survival of cancer patients.
We don't know yet if the same goes for other cancers like breast, prostate or lung, but it's a big step forward.
The programme's success hinged on consistent support. Participants met with fitness coaches every two weeks at first, then monthly, which helped them stick to their routines even after treatment ended.
While minor injuries such as muscle strains were slightly more common among those who exercised (19% compared to 12% in the control group), researchers emphasised that these issues were manageable and far outweighed by the significant survival benefits.
Potential downsides to exercise?
In contrast to the encouraging findings on structured exercise, a separate study presented in Chicago has raised questions about the potential downsides of extreme endurance training.
Researchers tracking marathon runners found a higher rate of polyps (small growths in the colon that can sometimes develop into cancer) compared with the general population. This unexpected finding has sparked a fresh debate about the effect of high-intensity exercise on long-term colon health.
However, context is needed. The study did not find higher cancer rates among runners, and most of the detected polyps were low risk.
Several possible explanations have been offered: endurance athletes may simply undergo more frequent screenings, leading to increased detection, or intense exercise might temporarily raise inflammation markers. Crucially, the overall risk of cancer remains lower in active people than in those who are more sedentary, reinforcing the well-established protective benefits of regular exercise.
This apparent contradiction highlights the medical community's evolving understanding of the "dose" of physical activity. While moderate exercise is consistently linked to significant health benefits , emerging data from endurance athletes suggests that extreme, high-intensity training may place different kinds of stress on the body's systems.
Researchers also suggest that factors such as dehydration during long-distance runs, changes in gut function, or the use of certain nutritional supplements common among endurance athletes could play a role in polyp development. These findings don't diminish the well-documented benefits of physical activity, but instead point to the importance of personalised, balanced health strategies.
For cancer survivors, the structured exercise study provides a message of practical hope. Participants aimed for the equivalent of about three hours of brisk walking per week, gradually increasing their activity levels over time.
The programme's social support was key, with fitness coaches helping participants tailor their routines to match their abilities and recovery needs.
Exercise is believed to affect key biological processes - including insulin sensitivity, inflammation and immune function - that play important roles in cancer development and progression. Ongoing research is analysing participants' blood samples to better understand these mechanisms and eventually create personalised exercise "prescriptions" based on an individual's genetic profile.
While the findings from marathon runners are less conclusive, they still offer practical takeaways. The research suggests that although vigorous exercise is generally beneficial, high-intensity athletes may face a higher risk of developing polyps and should therefore consider regular colonoscopies as a precaution.
For the general public, these findings reinforce that combining moderate exercise with timely screenings offers the best protection against colon cancer, a disease that remains the fourth most common worldwide and is alarmingly increasing among young people .
For both patients and athletes, these findings highlight a central truth: movement matters, but the right approach is crucial. Colon cancer survivors now have proven tools to reduce recurrence through structured exercise, while endurance enthusiasts gain motivation to pair their training with preventative care.
As science continues unravelling the intricate dance between activity and biology, one message remains clear: whether recovering from illness or chasing personal bests, informed exercise combined with medical guidance is the most reliable path to long-term health.
Justin Stebbing does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
