Risk of postcolonoscopy colorectal cancer following single-session endoscopic polypectomy: a retrospective cohort...

Colonoscopy is essential for colorectal cancer prevention. In Japan, two primary strategies for polypectomy are employed: single-session polypectomy, which combines diagnostic and therapeutic procedures in a single session, and deferred polypectomy, which is performed after a diagnostic colonoscopy. However, the impact of different polypectomy strategies remains unclear. This study aimed to investigate this evidence gap by comparing the postcolonoscopy colorectal cancer (PCCRC) incidence between the two strategies.

This retrospective cohort study used data from the Japan Medical Data Center claims database. Patients aged 40-70 years who underwent initial therapeutic colonoscopy between April 2012 and December 2018 were included. The primary outcome was the incidence of PCCRC during the 4-year follow-up period. For primary analysis, the weighted hazard ratio (HR) was calculated using the Cox hazard model with inverse probability of treatment weighting (IPTW) and inverse probability of censoring weighting (IPCW).

Among the 86 016 patients included, 71 027 were assigned to the single-session polypectomy group and 14 989 were assigned to the deferred polypectomy group. The incidence rates of PCCRC were 0.46 and 0.34 per 1000 person-years in the single-session and deferred polypectomy groups, respectively. The weighted HR with IPTW and IPCW in the single-session polypectomy group was 2.61 (95% confidence intervals: 1.25-5.44) compared to the deferred polypectomy group.

This study provides the first large-scale evidence that single-session polypectomy is associated with a higher risk of PCCRC compared to deferred polypectomy. Our findings highlight the need to improve diagnostic accuracy during therapeutic colonoscopy and further optimize single-session polypectomy techniques.