For decades, doctors have recommended adopting a healthy lifestyle to lower the risk of developing cancer. But until now there has been little evidence of the impact it could have after diagnosis, with scant support for incorporating exercise into patients’ routines.
However, a study has suggested that a structured exercise routine can, in fact, reduce the risk of death for people with colon cancer by more than a third.
The results, unveiled recently in Chicago at the American Society of Clinical Oncology (ASCO) annual meeting, the world’s largest cancer conference, could transform how colon cancer is treated around the world, the researchers said.
The scientists hope the findings will prompt healthcare providers to integrate exercise plans into routine cancer care.
Dr Julie Gralow, the chief medical officer of ASCO, who was not involved in the decade-long study, said the quality of its findings was the “highest level of evidence” and would lead to “a major shift in understanding the importance of encouraging physical activity during and after treatment”.
The CO21 CHALLENGE trial, published in the New England Journal of Medicine, followed 889 people with colon cancer (90% had stage three disease) across six countries – US, UK, Australia, France, Canada and Israel.
Patients were randomly assigned to take part in a structured exercise programme (445) or to just receive a healthy lifestyle booklet (444).
Those in the exercise group worked with a personal trainer twice a month for coaching sessions and supervised exercise sessions, and later once a month, for a total of three years.
Their weekly target was the equivalent of three to four walks of between 45 and 60 minutes, but patients could choose how they got more active. Some went kayaking or skiing, for instance.
Activities were tailored to the individual, from brisk walking to gym-based circuit training. After five years, 80% of the patients who followed the tailored exercise regime were cancer-free, compared with 74% who were offered just health education materials.
This means the risk of dying, cancer coming back, or developing a new cancer was 28% lower in the exercise group.
After eight years, survival rates were 90% in the exercise group compared with 83% in the health education group, representing a 37% lower risk of death.
“After completing surgery and chemotherapy, about 30% of patients with high-risk stage two and stage three colon cancer will eventually experience recurrence of their disease,” said the study’s lead author, Dr Christopher Booth, of Queen’s University in Kingston, Canada. “As oncologists, one of the most common questions we get asked by patients is ‘what else can I do to improve my outcome?’
“These results now provide us with a clear answer: an exercise programme that includes a personal trainer will reduce the risk of recurrent or new cancer, make you feel better and help you live longer.”
Professor Charles Swanton, the chief clinician of Cancer Research UK, which funded the UK arm of the study, said: “This fascinating study captures the power of exercise to transform people’s health and boost their chances of surviving cancer after treatment. For an intervention that isn’t a drug, exercise offers remarkable benefits for patients.”
More than 31 000 people in the UK die from colon cancer every year, according to Cancer Research UK.
The study was part-funded by Cancer Research UK’s Stand Up To Cancer campaign and carried out in collaboration with the Canadian Cancer Trials Group (CCTG).
Asked to put the effect of exercise on cancer patients’ outcomes into context, Gralow told The Guardian: “We titled (the session it was presented in) As Good as a Drug. I would have retitled it Better than a Drug, because you don’t have all the side effects.
“It’s the same magnitude of benefit of many drugs that get approved for this kind of magnitude of benefit – 28% decreased risk of occurrence, 37% decreased risk of death. Drugs get approved for less than that, and they’re expensive and they’re toxic.
“When I started three decades ago it was still the era where we’d be gentle and say, don’t overdo yourself when you’re on chemo. We’ve reversed that,” she added. “I would say exercise is better than a drug.”
Professor Vicky Coyle, UK lead researcher and clinical professor at Queen’s University Belfast, said the study gives “clear and encouraging” evidence that physical activity can reduce colon cancer mortality.
“We now need to work with policymakers and healthcare providers to embed exercise into treatment plans where appropriate,” she told The Independent.
While this study followed only colon cancer patients, Gralow said there was no reason to think the findings would not be applicable across other cancers.
Booth said trials for other cancers would be needed, but added that data from this study suggested there were lower breast and prostate cancer occurrences in the exercise group.
The researchers said more work is needed to explore the biological mechanisms behind exercise’s effect on cancer, but the evidence is already strong enough to prompt urgent action.
Study details
Structured Exercise after Adjuvant Chemotherapy for Colon Cancer
Kerry Courneya, Janette Vardy, Christopher O’Callaghan et al.
Published in New England Journal of Medicine on 1 June 2025
Abstract
Background
Preclinical and observational studies suggest that exercise may improve cancer outcomes. However, definitive level 1 evidence is lacking.
Methods
In this phase 3, randomised trial conducted at 55 centres, we assigned patients with resected colon cancer who had completed adjuvant chemotherapy to participate in a structured exercise program (exercise group) or to receive health-education materials alone (health-education group) over a three-year period. The primary end point was disease-free survival.
Results
From 2009 through 2024, a total of 889 patients underwent randomisation to the exercise group (445 patients) or the health-education group (444 patients). At a median follow-up of 7.9 years, disease-free survival was significantly longer in the exercise group than in the health-education group (hazard ratio for disease recurrence, new primary cancer, or death, 0.72; 95% confidence interval [CI], 0.55 to 0.94; P=0.02). The 5-year disease-free survival was 80.3% in the exercise group and 73.9% in the health-education group (difference, 6.4 percentage points; 95% CI, 0.6 to 12.2). Results support longer overall survival in the exercise group than in the health-education group (hazard ratio for death, 0.63; 95% CI, 0.43 to 0.94). The 8-year overall survival was 90.3% in the exercise group and 83.2% in the health-education group (difference, 7.1 percentage points; 95% CI, 1.8 to 12.3). Musculoskeletal adverse events occurred more often in the exercise group than in the health-education group (in 18.5% vs. 11.5% of patients).
Conclusions
A three-year structured exercise program initiated soon after adjuvant chemotherapy for colon cancer resulted in significantly longer disease-free survival and findings consistent with longer overall survival.
NEJM article – Structured Exercise after Adjuvant Chemotherapy for Colon Cancer (Open access)
See more from MedicalBrief archives:
More exercise advised for cancer patients – Chinese meta-analysis
Exercise may cut cancer mortality – SA study
High Intensity Training regimen may inhibit prostate cancer growth — ERASE trial