Physical Activity and Male Colorectal Cancer Survival

Background: Although physically active individuals have a lower risk of developing colorectal cancer, few studies have examined whether exercise benefits colorectal cancer survivors. Methods: Derived from the Health Professionals Follow-up Study, we studied colorectal cancer-specific and overall mortality in a cohort of 668 men with a history of stage I to stage III colorectal cancer according to pre-defined physical activity categories after diagnosis. To minimize bias by occult recurrences, we excluded men who died within 6 months of their post diagnosis physical activity assessment. Results: In a cohort of men with colorectal cancer and no apparent metastases at diagnosis, 50.4% exercised at least 18 metabolic equivalent task (MET) hours per week. Increased physical activity was significantly associated with improved colorectal cancer-specific mortality (P = .002 for trend) and overall mortality (P < .001 for trend). Men who engaged in more than 27 MET hours per week of physical activity had an adjusted hazard ratio for colorectal cancer-specific mortality of 0.47 (95% confidence interval, 0.24-0.92) compared with men who engaged in 3 or less MET hours per week of physical activity. The apparent benefit of physical activity was seen regardless of age, disease stage, body mass index, diagnosis year, tumor location, and pre-diagnosis physical activity. Conclusion: In a large cohort of men with a history of nonmetastatic colorectal cancer, more physical activity was associated with a lower risk of colorectal cancer-specific and overall mortality.