Colon to Rectum
Lancet Gastroenterol Hepatol. 2022;7(8):747–54
Serrated polyp detection and risk of interval post-colonoscopy colorectal cancer: A population-based study
Background: Adenoma detection rate (ADR) is a well-established quality indicator for colonoscopy and is inversely associated with the incidence of interval post-colonoscopy colorectal cancer (CRC). However, interval post-colonoscopy CRCs frequently develop from serrated polyps, which are not included in the ADR. Therefore, the proximal serrated polyp detection rate (PSPDR) has been proposed as a quality indicator, but its association with interval post-colonoscopy CRC has not been studied. The aim of the present study was to evaluate this potential association based on data collected in the Dutch CRC screening program.
Methods: In this population-based study, using colonoscopy data from the Dutch fecal immunochemical test-based CRC screening program and cancer data from the Netherlands Cancer Registry, the authors evaluated the association between endoscopists’ individual PSPDR and their patients’ risk of interval post-colonoscopy CRC with a shared frailty Cox proportional-hazard regression analysis. Participants in the screening program who were eligible for inclusion were aged 55–76 years, had a positive fecal immunochemical test (cut-off 15 μg Hb/g feces at start and changed mid-2014 to 47 μg Hb/g feces), were asymptomatic, and underwent a colonoscopy between January 1, 2014, and December 31, 2020. The PSPDR was defined as the proportion of colonoscopies in which at least 1 serrated polyp proximal to the descending colon was detected, confirmed by histopathology. The ADR was defined as the proportion of all colonoscopies in which at least 1 conventional adenoma was detected, confirmed by histopathology. Detection rates were determined for each endoscopist individually. The authors additionally evaluated the risk of interval post-colonoscopy CRC for endoscopists with a PSPDR and ADR above the median versus endoscopists with either 1 or both parameters below the median.
Findings: During the study period, 329,104 colonoscopies were done, of which 277,555, done by 441 endoscopists, were included in the PSPDR calculations. The median PSPDR was 11.9% (interquartile range [IQR], 8.3–15.8%) and median ADR was 66.3% (IQR, 61.4–69.9%). The correlation between the PSPDR and ADR was moderate (r = 0.59; p < 0.0001). During a median follow-up of 33 months (IQR, 21–42 months), 305 interval post-colonoscopy CRCs were detected. For each percentage point increase in PSPDR, the adjusted interval post-colonoscopy CRC hazard was 7% lower (hazard ratio [HR] = 0.93, 95% confidence interval [CI]: 0.90–0.95; p < 0.0001). Compared with endoscopists with a PSPDR > 11.9% and ADR > 66.3%, the HR of interval post-colonoscopy CRC for endoscopists with a low PSPDR and high ADR was 1.79 (95% CI: 1.22–2.63), for endoscopists with a high PSPDR and low ADR was 1.97 (95% CI: 1.19–3.24), and for endoscopists with a low PSPDR and low ADR was 2.55 (95% CI: 1.89–3.45).
Interpretation: The proximal serrated polyp detection rate (PSPDR) of an endoscopist is inversely associated with the incidence of interval post-colonoscopy colorectal cancer (CRC). Implementation of PSPDR monitoring, in addition to adenoma detection rate monitoring, could optimize CRC prevention.