Dose-response Effects of Aerobic Exercise Among Colon Cancer Survivors: A Randomized Phase II Trial

Postdiagnosis physical activity is associated with a lower risk of disease recurrence among survivors of colon cancer. Thirty-nine stage I to III survivors of colon cancer were randomized to usual-care control, 150 minutes per week, or 300 minutes per week of aerobic exercise for 6 months. Exercise was feasible, well-tolerated, and elicited changes in physiologic markers associated with disease recurrence. This study informs future phase II/III trials. Background: Observational studies suggest that higher volumes of physical activity are associated with a lower risk of disease recurrence among survivors of colon cancer. However, the feasibility and safety of prescribing higher volumes of physical activity to survivors of colon cancer are unknown. Furthermore, the pathways through which exercise may reduce disease recurrence are unknown. Patients and Methods: Survivors of stage I to III colon cancer were randomized to usual-care control, 150 minutes per week of aerobic exercise (low-dose), or 300 minutes per week of aerobic exercise (high-dose). Changes in soluble intercellular adhesion molecule-1 and vascular adhesion molecule-1 prognostic biomarkers were examined. Results: From January 2015 to February 2016, 39 patients were enrolled (n = 13 usual-care control; n = 14 low-dose; n = 12 high-dose), and 38 participants completed the study (97% follow-up). Over 6 months, the low-dose group completed 142 minutes per week (92.8% adherence), and the high-dose group completed 247 minutes per week (89.0% adherence) of exercise. Compared with the control group, changes in soluble intercellular adhesion molecule-1 were −134.9 ng/mL (95% confidence interval, −238.1 to −31.6 ng/mL) in the low-dose group and −114.8 ng/mL (95% confidence interval, −222.5 to −7.1 ng/mL) in the high-dose group (linear P _trend =.023; nonlinear P _trend =.044). No changes were observed for soluable vascular adhesion molecule-1 (linear P _trend =.791; nonlinear P _trend =.604). Non-serious adverse events occurred at similar rates among randomized groups. No serious adverse events occurred. Conclusion: Higher volumes of moderate-intensity aerobic exercise, up to 300 minutes per week, are feasible, safe, and elicit favorable changes in prognostic biomarkers among patients recently treated for stage I to III colon cancer. These data can be used to guide clinical recommendations for patients, and inform future trials.