Physician adenoma detection rates and risk of post-colonoscopy colorectal cancer in a sequential screening programme: a retrospective cohort study.

OBJECTIVES: Long-term colorectal cancer (CRC) monitoring is common in Asia, but assessing colonoscopy effectiveness through adenoma detection rates (ADRs) remains uncommon. This study aimed to identify potential associations between ADR and risk of post-colonoscopy CRC (PCCRC). METHODS: This retrospective, longitudinal, observational study included participants (aged 40-74 years) with initial positive results and subsequent colonoscopy recruited from a community-based, multicentre, CRC screening programme from January 2012 to December 2022 in Tianjin, China. ADR was defined as the proportion of colonoscopies in which at least one adenoma was detected at the provider level. The primary outcome was PCCRC, defined as any CRC diagnosed 6 months after initial colonoscopy. ADR groups were categorised according to quartile distribution (<42%, 42%-55%, 55%-64% and >64%) or dichotomised as at or above vs below the median for statistical analyses. PCCRC incidence rates were expressed as the number of events per 1000 person-years. RESULTS: Among 9957 included participants, 116 PCCRC cases were detected in 33 881 person-years of follow-up. PCCRC incidence rates per 1000 person-years were 4.34, 3.76, 2.62 and 2.69 from the lowest to the highest ADR group, respectively. ADR was significantly inversely associated with PCCRC risk. Participants in the highest ADR group had 49% lower risk of PCCRC than those in the low ADR group (adjusted HR 0.51, 95% CI 0.29 to 0.88). Multivariate-adjusted restricted cubic spline analyses identified a linear dose-response relationship between ADR and PCCRC risk. CONCLUSIONS: This study illustrates the relationship between endoscopist competence, as measured by ADR, and CRC risk after colonoscopy, which can guide assessment of monitoring programmes.