Associations of recreational physical activity and leisure time spent sitting with colorectal cancer survival

Purpose Little is known about the association of recreational physical activity or leisure time spent sitting with survival after colorectal cancer diagnosis. This study examined the associations of prediagnosis and postdiagnosis recreational physical activity and leisure time spent sitting with mortality among patients with colorectal cancer. Patients and Methods From a cohort of adults without colorectal cancer at baseline in 1992-1993, we identified 2,293 participants who were diagnosed with invasive, nonmetastatic colorectal cancer up to mid-2007. At baseline, before their cancer diagnosis, and again after their cancer diagnosis, participants completed detailed questionnaires that included information concerning recreational physical activity and leisure time spent sitting. Results During a maximum follow-up of 16.1 years after colorectal cancer diagnosis, 846 patients with colorectal cancer died, 379 of them from colorectal cancer. Engaging in 8.75 or more metabolic equivalent (MET) hours per week of recreational physical activity (equivalent to approximately 150 minutes per week of walking) compared with fewer than 3.5 MET hours per week was associated with lower all-cause mortality (prediagnosis physical activity: relative risk [RR], 0.72; 95% CI, 0.58 to 0.89; postdiagnosis physical activity: RR, 0.58; 95% CI, 0.47 to 0.71). Spending 6 or more hours per day of leisure time sitting compared with fewer than 3 hours per day was associated with higher all-cause mortality (prediagnosis sitting time: RR, 1.36; 95% CI, 1.10 to 1.68; postdiagnosis sitting time: RR, 1.27; 95% CI, 0.99 to 1.64). Conclusion More recreational physical activity before and after colorectal cancer diagnosis was associated with lower mortality, whereas longer leisure time spent sitting was associated with higher risk of death.