Associations of postdiagnosis changes in physical activity with all-cause mortality among patients with stage I-IIA colorectal cancer.

Abstract

87 Background: Several observational studies show an association between physical activity (PA) at diagnosis and reduced risk of mortality among colorectal cancer (CRC) patients, but there has been limited research examining the potential benefit of changes in PA levels after CRC diagnosis. Here we investigate the association between change of PA and all-cause mortality in patients with stage I-IIA CRC receiving resection with curative intent. Methods: Data were used from two large Dutch CRC cohort studies (PLCRC & COLON), which assessed PA at diagnosis (T0), six (T6) and twelve (T12) months after diagnosis, using the SQUASH questionnaire. A total of 2540 stage I-IIA CRC patients with repeated PA measures (i.e. a T0 and at least a T6 or T12 questionnaire) were used for this analysis. Total PA was quantified by calculating Metabolic Equivalent Task (MET) hours per week and categorized as low, moderate, and high PA, based on tertiles of an age- and sex-matched sample of the general population. PA changes were evaluated at T6 and T12 relative to T0. Being active was defined per timepoint as being in the moderate or high total PA group, or adhering to the PA guideline (minimum of 150 minutes per week of moderate-intensity PA). Cox proportional hazards models were used to study the association between PA variables and all-cause mortality, adjusted for age, sex, BMI, and tumor location (colon vs rectum). Results: Median follow-up time was 35 months (interquartile range 19 – 55) during which a total of 133 deaths occurred. Being active at both T0 and T6 compared to being inactive at these timepoints, was associated with a lower rate of all-cause mortality for both PA variables (adjusted hazard ratio (HR) 0.39 [95% confidence interval 0.24-0.63] and 0.41 [0.23-0.72] for total PA and guideline adherence, respectively). Similar results were found when comparing T12 to T0 (being active according to total PA HR 0.20 [0.09-0.42] and guideline adherence HR 0.31 [0.14-0.72]). Changing to either activity or inactivity at T6 or T12 was not significantly associated with all-cause mortality (Table). Conclusions: Maintaining a physically active lifestyle following surgery for stage I to IIA CRC is associated with longer overall survival, reinforcing the recommendations for physical activity. [Table: see text]