Physical activity and male colorectal cancer survival

Abstract

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 predefined physical activity categories after diagnosis. To minimize bias by occult recurrences, we excluded men who died within 6 months of their postdiagnosis 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 prediagnosis 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.

Figure 1. Log hazard smoothing spline plot

Note: MET = metabolic equivalent task. Solid line is the log hazard ratio and dashed lines represent 95% confidence interval

Figure 2

Cumulative incidence of colorectal cancer-specific deaths (log rank p = 0.01)

Figure 3

Kaplan Meier

Figure 4

Stratified Analysis of Disease-Free Survival (Comparison of < 27 MET-hours/week to > 27 MET-hours/week of Exercise)