The CHALLENGE trial: can a structured exercise program after colon cancer treatment help you live longer?
A landmark phase III trial found that patients who followed a supervised exercise program after completing chemotherapy for colon cancer had a 28% lower risk of their cancer coming back — and a 37% lower risk of dying.
Is this relevant to your situation?
This trial enrolled patients who had:
What was this trial trying to do?
This trial asked whether structured, supervised exercise — not just general advice to "stay active" — could reduce the chance of colon cancer coming back after standard treatment. It also looked at whether exercise improved how patients felt physically and whether it helped them live longer overall.
Why did researchers ask this question?
For years, oncologists had observational data suggesting that patients who were more physically active after a colon cancer diagnosis tended to do better — lower recurrence rates, better survival. But observational data has an important limitation: healthier, more active patients might simply be healthier to begin with. Without a randomised trial — where patients are randomly assigned to exercise or not — you can't be sure exercise is causing the benefit.
The CHALLENGE trial was designed to finally answer that question with the gold standard of evidence: a randomised controlled trial. It took seventeen years from design to publication, enrolling 889 patients across 55 centres in six countries. The question it set out to answer was straightforward, even if the answer took a long time to arrive: if we help patients exercise in a structured way after treatment, does it change their chances of staying cancer-free?
Disease-free survival (DFS) measures the time from the end of treatment until cancer returns, a new cancer develops, or death — whichever comes first. It is the most common way to measure whether a treatment reduces recurrence in early-stage cancer trials.
What was tested, and how?
Between 2009 and 2024, 889 patients who had completed surgery and adjuvant chemotherapy for stage III or high-risk stage II colon cancer were randomly assigned to one of two groups. Patients were enrolled 2 to 6 months after finishing chemotherapy, and 90% had stage III disease.
The exercise group (445 patients) worked with a certified physical activity consultant for three years. The program was structured in three phases: intensive support every two weeks in the first six months (in person), then fortnightly in months 7–12 (in person or virtual), then monthly for the final two years. The goal was to gradually increase aerobic exercise by at least 10 MET-hours per week — roughly equivalent to adding 45–60 minutes of brisk walking three or four times per week. Patients chose their own type of exercise.
The comparison group (444 patients) received health education materials encouraging physical activity and healthy nutrition, along with standard cancer surveillance. Importantly, this group also became somewhat more active over time — which actually means the true benefit of the structured program may be even larger than the trial results suggest.
Patients were followed for a median of 7.9 years. The trial was conducted at 55 centres across six countries — primarily Canada and Australia, with additional sites in the United Kingdom, France, the United States, and Israel.
One of the most common conversations I have had over the years goes something like this. A patient — let's call him Robert — comes to see me three months after finishing chemotherapy for stage III colon cancer. It was tough, he had an allergic reaction to one of the drugs, and then battled loose stools in the last couple of cycles. He needed a special kind of intravenous line (called a PICC line), and was no doubt a very happy camper when he rang the gong at the end of all of it. Now, three months later, he feels pretty much back to his normal self, except when he walks on a cold floor and feels the tingling in his toes. Now that he has finished all the chemotherapy we prescribed, he has a question he's been turning over for weeks.
"Is there anything more I can do?" he asks. "To help stop it coming back?"
For most of my career, my honest answer was incomplete. I could tell him that a healthy lifestyle, which included exercise, was probably helpful, but I couldn't be more concrete than that. The CHALLENGE trial has changed that answer.
What did the trial find?
The results were striking — and clinically meaningful. Patients in the structured exercise group were significantly less likely to have their cancer return or to die during the follow-up period.
Key findings
One striking finding that has received less attention: the benefit was not only driven by fewer colon cancer recurrences. The exercise group had far fewer new primary cancers — particularly breast cancer (0.4% vs 2.7%), prostate cancer (1.1% vs 2.0%), and new colorectal cancers (0% vs 1.1%). This suggests exercise may be doing something broader — possibly through immune surveillance, reduced inflammation, or improved metabolic signalling — rather than simply targeting residual colon cancer cells.
Interestingly, exercise did not reduce body weight or waist circumference, which suggests weight loss is not the main explanation for the benefit.
To put the survival benefit in perspective: the trial authors noted that the magnitude of benefit from exercise was similar to that of many currently approved standard drug treatments for colon cancer — a striking finding for an intervention that costs far less and has broad health benefits beyond cancer.
View the full trial record on ClinicalTrials.gov The Results tab includes links to associated publications — the NEJM paper may be accessible via your library or institution
NCT00819208 ↗What does this mean for patients?
This is the first randomised controlled trial to conclusively show that structured exercise — not just general advice to stay active, but a supported, personalised program — reduces the risk of colon cancer coming back and helps patients live longer. The trial authors concluded that this evidence supports incorporating structured exercise into standard care.
For patients who have completed treatment for stage III or high-risk stage II colon cancer, asking your oncologist about a structured exercise program is now a reasonable and evidence-backed conversation. The goal is not an athlete's training regime — it is roughly 45–60 minutes of brisk walking three or four times per week, with professional support to help you build up to it and sustain it over three years.
The trial does not yet tell us whether these results apply to other cancers, but the decreases rates of breast and prostate cancer certainly give us pause, and are actively being studied as well.
I love to talk about the CHALLENGE trial when patients come to see me a few months after chemotherapy. Patients like Robert, who are motivated and healthy, take the advice in stride, and start counting daily steps almost immediately. The beauty of the trial was that it did not involve complicated weight lifting or fancy machines — just a couple more hours of walking per week. Now that's a prescription I'll always be eager to write.
What does 10 MET-hours per week actually look like?
MET-hours measure exercise intensity multiplied by time. Brisk walking has an intensity of 4 METs — so one hour of brisk walking equals 4 MET-hours. To reach the trial's goal of adding 10 MET-hours per week, you have options. You choose the type, pace, and schedule that fits your life.
Questions & comments
Have a question about this trial? Ask below. Questions are read and answered by the site. We can’t give personal medical advice, but we’re glad to explain the research more clearly.