A randomized phase III trial of the impact of a structured exercise program on disease-free survival (DFS) in stage 3 or high-risk stage 2 colon cancer: Canadian Cancer Trials Group (CCTG) CO.21 (CHALLENGE).

Abstract

LBA3510 Background: Multiple observational studies have reported that post-diagnosis physical activity (PA) is associated with reduced recurrence rates in early-stage colon cancer but epidemiologic data is limited by confounding and reporting bias. CCTG CO.21 was designed to test the hypothesis that a meaningful increase in recreational PA after adjuvant therapy is achievable and will improve DFS in stage 3 or high-risk stage 2 colon cancer. Methods: CCTG CO.21 enrolled patients at 55 sites in 6 countries. Patients with resected stage 3 or high-risk stage 2 colon cancer who had received adjuvant chemotherapy were randomized to a structured exercise program (SEP) or health education materials (HEM). HEM participants received education materials promoting PA and healthy nutrition in addition to standard surveillance. SEP participants worked with a PA consultant who delivered an exercise intervention using behavior change methodology over 3 years. The SEP goal was to increase recreational PA by at least 10 MET-hours/week from baseline during the first 6 months and sustain this for 3 years. Participants chose the type, frequency, intensity and duration of aerobic exercise. The primary endpoint is DFS compared by a stratified log-rank test performed on an intention-to-treat basis. Secondary endpoints include overall survival (OS) and patient-reported outcomes (SF-36 physical function scale was primary PRO). Results: Between 2009 and 2024,889 participants were randomized to SEP (n=445) or HEM (n=444); 51% female, median age 61 years, 90% stage 3 disease. Compared to HEM, SEP resulted in statistically significant improvements in recreational PA, predicted VO2max, and 6-minute walk distance, all maintained over the 3-year intervention period. With a median follow-up of 7.9 years, 224 DFS events (93 in SEP and 131 in HEM) and 107 deaths (41 in SEP and 66 in HEM) were observed. 5-year DFS was 80% in SEP and 74% in HEM (HR 0.72; 95% CI 0.55-0.94; p=0.017). 8-year OS was 90% in SEP and 83% in HEM (HR=0.63; 95% CI=0.43-0.94; p=0.022). SF-36 physical function was substantially improved with SEP at 6 months (mean change scores 7.42 vs 1.10, p<0.001) and was sustained to 24 months. In the safety analysis, 19% (79/428) of patients on SEP reported any grade of musculoskeletal adverse event (MSK AE) over the course of the study, compared to 12% (50/433) on HEM. 10% (8/79) of MSK AE on SEP were considered to be related to participation in the PA program. Conclusions: Inpatients with stage 3 and high-risk stage 2 colon cancer, a 3-year structured exercise program initiated shortly after completion of adjuvant chemotherapy improves DFS, OS, patient-reported physical functioning, and health-related fitness. Health systems should incorporate structured exercise programs as standard of care for this patient population. Clinical trial information: NCT00819208 .