Effects of a Structured Exercise Program on Physical Activity and Fitness in Colon Cancer Survivors: One Year Feasibility Results from the CHALLENGE Trial.

Background: There is strong interest in testing lifestyle interventions to improve cancer outcomes; however, the optimal methods for achieving behavior change in large-scale pragmatic trials are unknown. Here, we report the 1-year feasibility results for exercise behavior change in the Canadian Cancer Trials Group CO.21 (CHALLENGE) Trial.

Methods: Between 2009 and 2014, 273 high-risk stage II and III colon cancer survivors from 42 centers in Canada and Australia were randomized to a structured exercise program (SEP; n = 136) or health education materials (HEM; n = 137). The primary feasibility outcome in a prespecified interim analysis was a difference between randomized groups of ≥5 metabolic equivalent task (MET)-hours/week in self-reported recreational physical activity (PA) after at least 250 participants reached the 1-year follow-up. Secondary outcomes included health-related fitness.

Results: The SEP group reported an increase in recreational PA of 15.6 MET-hours/week compared with 5.1 MET-hours/week in the HEM group [mean difference = +10.5; 95% confidence interval (CI) = +3.1-+17.9; P = 0.002]. The SEP group also improved relative to the HEM group in predicted VO2max (P = 0.068), 6-minute walk (P < 0.001), 30-second chair stand (P < 0.001), 8-foot up-and-go (P = 0.004), and sit-and-reach (P = 0.08).

Conclusions: The behavior change intervention in the CHALLENGE Trial produced a substantial increase in self-reported recreational PA that met the feasibility criterion for trial continuation, resulted in objective fitness improvements, and is consistent with the amount of PA associated with improved colon cancer outcomes in observational studies.

Impact: The CHALLENGE Trial is poised to determine the causal effects of PA on colon cancer outcomes. Cancer Epidemiol Biomarkers Prev; 25(6); 969-77. ©2016 AACR.