CHALLENGE: a structured exercise programme after chemotherapy improves survival in colon cancer
In CHALLENGE, three years of supervised, goal-based exercise after adjuvant chemotherapy for colon cancer reduced recurrence or death by 28% and deaths by 37%, the first randomised proof that exercise itself improves cancer survival.
CHALLENGE (CCTG CO.21) randomised 889 patients with resected stage III or high-risk stage II colon cancer who had completed adjuvant chemotherapy to a 3-year structured exercise programme (behavioural support and supervised sessions, targeting an increase of at least 10 MET-hours per week) or to health-education materials alone. The primary endpoint was disease-free survival.
After a median follow-up of nearly 8 years, 5-year DFS was 80.3% with exercise versus 73.9% with education (HR 0.72). Eight-year overall survival was 90.3% versus 83.2% (HR 0.63). Physical functioning improved and musculoskeletal adverse events were more common in the exercise arm.
This is the first phase 3 trial to show that an exercise intervention, rather than exercise as a correlate, lengthens survival in cancer.
- Five-year disease-free survival 80.3% vs 73.9% (HR 0.72, 95% CI 0.55-0.94)
- Eight-year overall survival 90.3% vs 83.2% (HR 0.63, 95% CI 0.43-0.94)
- Median follow-up 7.9 years across 55 centres in Canada, Australia, the UK, France, Israel and the US
- Musculoskeletal adverse events 18.5% vs 11.5%; the programme was delivered by physical activity consultants over 3 years
For colon cancer survivors, a prescribed, supported exercise programme is now an evidence-based treatment with a survival benefit comparable to many drugs. Health systems will need to fund exercise consultants as they fund chemotherapy. The trial does not tell us whether unsupervised advice achieves the same.
- The intervention was intensive (behavioural support for 3 years); uptake and cost in routine care are untested
- Participants were fit enough to enrol and motivated; benefit in frail or sedentary populations is unproven
- Open-label; DFS assessment could be influenced by differential surveillance
- Recruitment took 15 years, so adjuvant regimens evolved during the trial