Optimal withdrawal time in initial surveillance colonoscopy after colorectal cancer surgery: comparison between anterior/low anterior resection and right hemicolectomy.

Purpose: This study aimed to investigate the optimal withdrawal time (WT) for initial surveillance colonoscopy after curative resection for colorectal cancer (CRC) by comparing anterior/low anterior resection (AR/LAR) and right hemicolectomy (RHC) groups.

Methods: This retrospective study analyzed 1,212 patients who underwent initial surveillance colonoscopy after CRC resection between 2015 and 2022. The patients were divided into the AR/LAR (n = 846) and RHC (n = 366) groups. The optimal WT was determined using receiver operating characteristic curve analysis and validated using logistic regression models. The adenoma and advanced neoplasia detection rates (ADR/ANDR) were evaluated based on the optimal WT.

Results: The optimal WT was 7 and 6 minutes in the AR/LAR and RHC groups, respectively. In multivariate analysis, WT ≥7 and ≥6 minutes in the AR/LAR (odds ratio [OR], 2.38; 95% confidence interval [CI], 1.75-3.24; P < 0.001) and RHC (OR, 2.64; 95% CI, 1.59-4.39; P = 0.001) groups, respectively, were significant factors for adenoma detection. In the AR/LAR group, ADR was 41.5% for WT ≥7 minutes compared to 21.9% for WT <7 minutes (P < 0.001). In the RHC group, ADR for WT ≥6 minutes was 33.9% compared to 15.8% for WT <6 minutes (P < 0.001). The ANDR also significantly improved with longer WTs in both groups.

Conclusion: This study suggests that a minimum WT of 7 and 6 minutes for AR/LAR and RHC patients, respectively, during the initial surveillance colonoscopy after CRC resection is optimal for maintaining a satisfactory ADR and ANDR. These findings highlight the importance of tailoring colonoscopic procedures according to the type of surgical resection.