Society: AGA

Introduction & Aim:
Metachronous colorectal neoplasm (meta-CRN) may occur after colonoscopic polypectomy and subjects with metabolic derangement, such as metabolic syndrome and non-alcoholic liver disease (NAFLD), are associated with a higher risk of meta-CRN. Although our previous work demonstrated that active exercise after polypectomy can reduce the risk of metachronous advanced colorectal neoplasm (meta-ACRN), how it acts in high-risk subjects is unclear. The aim of this study is to elucidate whether exercise is an effective and specific preventive strategy against meta-ACRN among subjects with metabolic derangements.

Material & Method:
We retrospectively analyzed 3,231 subjects who underwent screening (index) colonoscopy with polypectomy and subsequent surveillance colonoscopy between January 2009 and December 2019. The baseline metabolic profiles of all participants were obtained at the date of index colonoscopy. All participants were also asked to complete a standard medical questionnaire before surveillance colonoscopy regarding their average exercise status after index colonoscopy. The risk of meta-ACRN after index colonoscopy in subjects with and without active exercise was analyzed by Kaplan-Meier (KM) analysis. Cox regression models are constructed for multivariate analysis.

Result
Of those 3,231 who were enrolled, the median age was 56 years old and 2247(65.5%) were men. Among the study cohort, 2450 (75.8%) subjects were classified as metabolic derangement (having at least one of the following factors: central obesity, elevated triglyceride, low HDL, hypertension and impaired fasting glucose) and 1134 (35.1%) subjects had NAFLD. A total of 1,365 (42.2%) subjects developed at least one meta-CRN including 166 (5.1%) subjects with meta-ACRN during a mean follow-up time of 3.4-year. After KM analysis, subjects adopting a more active exercise habitus (≥ 15 metabolic equivalent of tasks/week) after index polypectomy was associated a significantly reduced risk of meta-ACRN (log-rank p=0.02). In the multivariable analysis, the adjusted hazard ratio (aHR) of developing meta-ACRN after engaging active exercise after polypectomy was 0.52 (95% confidence interval (CI) = 0.63–0.75) for those with metabolic derangement and 0.24 (95% CI = 0.13–0.44) for those with NAFLD. On the other hand, the association between exercise status and meta-ACRN risk was non-significant in those with healthy metabolic status (aHR:0.65; 95% CI: 0.32-1.33)

Conclusion:
The study results confirmed the protective effect of active exercise after index polypectomy in preventing meta-ACRN and further demonstrated that such an effect was mediated by the subjects' metabolic status. For preventing meta-ACRN more specifically and efficiently, active exercise should be strongly advised after screening colonoscopy and polypectomy to subjects with metabolic derangements and NAFLD.

Hsuan-Ho Lin

Appearances