Physical activity and survival of colorectal cancer patients: Population-based study from Germany.

Increasing evidence shows physical activity to be associated with improved colorectal cancer (CRC) prognosis. However, large-scale prospective patient cohorts, comprehensively ascertaining physical activity, comprehensively considering potential variation by CRC stage and considering specific outcome measures, are sparse. Therefore, we aimed to evaluate the association of lifetime and latest prediagnostic leisure time physical activity with relevant prognostic outcomes in a large population-based cohort of CRC patients. 3,121 patients, diagnosed with CRC in 2003-2010 (median age: 69 years), were interviewed on sociodemographic and lifestyle factors, medication and comorbidities. Cancer recurrence, vital status and cause of death were documented over a median follow-up time of 4.8 years. Associations between lifetime and latest prediagnostic leisure time physical activity and overall, CRC-specific, recurrence-free and disease-free survival were evaluated with Cox regression. Latest but not lifetime leisure time physical activity [in metabolic task hours per week (MET-h/wk)] was associated with decreased overall and CRC-specific mortality (>56.2 vs. ≤13.2 MET-h/wk: adjusted hazard ratio (aHR)Overall/latest  = 0.75; 95% confidence interval (CI) = 0.61-0.91; aHRCRC-specific/latest  = 0.81; 95% CI = 0.64-1.02). In particular lifetime and latest walking were associated with decreased mortality (>20 vs. 0-10 MET-h/wk of walking: aHROverall/latest  = 0.66; 95% CI = 0.56-0.77; aHRCRC-specific/latest  = 0.72; 95% CI = 0.60-0.87; aHROverall/lifetime  = 0.78; 95% CI = 0.66-0.93; aHRCRC-specific/lifetime  = 0.71; 95% CI = 0.58-0.86). Associations were particularly pronounced for lifetime walking in metastatic (stage IV) and for latest walking in nonmetastatic disease patients. Prediagnostic physical activity was associated with improved CRC prognosis. Associations might be restricted to certain activities or depend on (non)metastatic disease state. Further optimization of activity recommendations and increase of recommendation adherence may help to improve patients' prognosis.