Christopher M. Booth, MD, on a Structured Exercise Program for Patients With Colon Cancer

The Canadian Cancer Trials Group CO.21 Challenge trial was the first randomized controlled trial in any cancer to definitively ask the question whether exercise can improve cancer survival. Patients with colon cancer who had already completed surgery and adjuvant chemotherapy were eligible to be enrolled in this study. Patients were randomized to a control arm in which patients were given an informational booklet encouraging them to adopt a healthy lifestyle and to exercise, or the experimental arm where patients were given the same booklet, but they were also provided with a physical activity consultant for three years. And the goal of this physical activity consultant was to deliver behavior change intervention so that patients would change their lifestyle and over the first six months, gradually ramp up their exercise so that it increased by 10 metabolic hours per week. MET hours, a unit of exercise, and there's a number of different tables that will allow the exercise specialist to work with the patient to come up with an exercise prescription for the activities that make sense for that patient given their own lifestyle, whether it's a certain number of minutes of swimming, biking, running, jogging, kayaking, a prescription could be made to allow them to hit this target over the first six months. And the way this behavior change was done was over sessions, face-to-face sessions every two weeks. It would start with a motivational session to look at goal setting, time management, to review the exercise progress of the last month and to make plans for the next few weeks. And then there would be a supervised exercise session, usually on a treadmill or an exercise bike. And that happened every two weeks for the first six months as patients gradually ramped up their exercise. It continued for the next six months every two weeks. And then for year two and year three, there were monthly check-ins with the physical activity consultant and the patient to ensure that they maintained support to maintain that lifestyle intervention. The primary endpoint of the study was disease-free survival. The results quite frankly were astounding. They were really remarkable. The structured exercise program clearly allowed people to increase their exercise. Their physiologic measures of fitness also increased substantially. VO2 max and six-minute walk test, their quality of life and physical function improved, but what was even more remarkable is the survival benefit. So the disease-free survival hazard ratio was 0.72. So there was a 28% reduction in the risk of recurrent or new cancer. This translated to an absolute improvement of 6 percent, 74% versus 80% rates of disease-free survival at five years. That translates to for every 16 patients who went on the exercise program, one person was avoided having recurrent or new cancer. The overall survival benefits were also remarkable. There was a 37% reduction in the risk of death with a hazard ratio of 0.63, again both clinically significant and statistically significant. The eight-year overall survival rate was 83% in the control arm and 90% in the experimental arm. Again converting that to a number needed to treat, for every 14 patients who went on the exercise program, exercise saved one person's life. So really it's quite a remarkable magnitude of benefit. Looking at safety and toxicity, again, not surprisingly, there were no major differences except for a slight increase in the risk of musculoskeletal injury in the patients on the exercise arm. But in summary, this was the first clinical trial in the world that asked the question can exercise improve cancer survival? And clearly the answer is a resounding yes. And so as of now, we think that this is now a standard of care for patients with colon cancer and health systems need to provide this service. Knowledge of this benefit in itself is not necessarily going to be sufficient to allow most patients to change their lifestyle, sustain that change and realize the health benefits. We need providers, hospitals, cancer centers, payers and health systems to provide the structured exercise program as now a standard of care and part of standard cancer treatment for colon cancer.