Issue: October 2022
Fact checked byHeather Biele

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August 29, 2022
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Proximal serrated polyp detection may reduce incidence of post-colonoscopy CRC

Issue: October 2022
Fact checked byHeather Biele
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Improving proximal serrated polyp detection rate, along with adenoma detection rate, may increase colonoscopy effectiveness and reduce incidence of interval post-procedure colorectal cancer, according to new research.

“Serrated polyps progress to colorectal cancer via the serrated neoplasia pathway, and account for around 15% to 30% of sporadic colorectal cancers. ... Because of their indistinct color, vague borders and flat or sessile shape, the endoscopic detection and resection of serrated polyps is challenging,” David E. F. W. M. Van Toledo, MD, of the department of gastroenterology, hepatology and nutrition at Amsterdam University Medical Center, and colleagues wrote in The Lancet Gastroenterology and Hepatology. “As a result, serrated polyps are easily missed and often incompletely resected, which are both important contributors to interval post-colonoscopy colorectal cancers.”

The hazard ratio for interval post-colonoscopy colorectal cancer
Data derived from Van Toledo DEFWM, et al. Lancet Gastroenterol Hepatol. 2022;doi:10.1016/S2468-1253(22)00090-5.

In recent years, several parameters for serrated polyp detection, including the proximal serrated polyp detection rate (PSPDR), have been proposed. In a population-based study, Van Toledo and colleagues aimed to investigate the potential association between PSPDR and risk for interval post-colonoscopy CRC using data from the Dutch fecal immunochemical test-based CRC screening program and the Netherlands Cancer Registry. Eligible participants were aged 55 to 76 years, had a positive fecal immunochemical test and were asymptomatic at the time of colonoscopy. Researchers defined PSPDR as the proportion of colonoscopies in which at least one serrated polyp was detected proximal to the descending colon and confirmed by histopathology.

Researchers identified 277,555 colonoscopies performed by 441 endoscopists (median 542 colonoscopies per endoscopist) from 2014 to 2020. The median PSPDR was 11.9% and the adenoma detection rate (ADR) was 66.3%. During a median follow-up of 33 months, there were 305 cases of interval post-colonoscopy CRC detected with an incidence rate of four cases per 10,000 person-years of follow-up.

Study results showed each percentage point increase in PSPDR correlated with a 7% lower adjusted risk for interval post-colonoscopy CRC (HR = 0.93; 95% CI, 0.9-0.95), with a significant association between PSPDR and the incidence of advanced stage (HR = 0.94; 95% CI, 0.91-0.97), non-advanced stage (HR = 0.9; 95% CI, 0.87-0.94), proximal (HR = 0.94; 95% CI, 0.91-0.98) and distal CRC (HR = 0.91; 95% CI, 0.97-0.94). Risk for interval post-colonoscopy CRC declined with increased PSPDR quintile in trend analyses.

Compared with endoscopists with PSPDR and ADR above median values, endoscopists with low PSPDR and high ADR (HR = 1.79; 95% CI, 1.22-2.63); high PSPDR and low ADR (HR = 1.97; 95% CI, 1.19-3.24); and low PSPDR and low ADR (HR = 2.55; 95% CI, 1.89-3.45) had greater risk for interval post-colonoscopy CRC.

“Our study is the first to show a strong inverse association between endoscopists’ PSPDR and the incidence of interval post-colonoscopy colorectal cancer. This association cannot solely be explained by the correlation between the PSPDR and the ADR,” Van Toledo and colleagues concluded. “This finding suggests that improving endoscopists’ PSPDR could optimize colonoscopy effectiveness and reduce the incidence of interval post-colonoscopy colorectal cancer.”