Adenoma detection rate inversely associated with postcolonoscopy colorectal cancer after FIT screening

A study of an Italian fecal immunochemical test (FIT)-based screening program found a 2.35-fold risk increase in postcolonoscopy colorectal cancer among patients treated by endoscopists with the lowest versus highest adenoma detection rate.

In a fecal immunochemical test (FIT)-based screening program, adenoma detection rate (ADR) was inversely associated with postcolonoscopy colorectal cancer (PCCRC) risk.

Researchers conducted the retrospective population-based cohort study of a FIT-based CRC screening program between 2003 and 2021 in northeastern Italy. They included all patients with a positive FIT results who had a colonoscopy, and the regional cancer registry supplied information on any PCCRC diagnosed between six months and 10 years after colonoscopy. The researchers categorized endoscopist ADR into five groups: 20% to 39.9%, 40% to 44.9%, 45% to 49.9%, 50% to 54.9%, and 55% to 70%. The primary outcome was PCCRC, defined as any incident CRC diagnosed six months after index colonoscopy. Results were published Feb. 21 by Annals of Internal Medicine.

Of the 110,109 initial colonoscopies, 49,626 colonoscopies performed by 113 endoscopists between 2012 and 2017 were included. After 328,778 person-years of follow-up, 277 cases of PCCRC were diagnosed. The mean ADR was 48.3% (range, 23% to 70%). Incidence rates of PCCRC from lowest to highest ADR group were 13.13, 10.61, 7.60, 6.01, and 5.78 per 10,000 person-years. There was a significant inverse association between ADR and PCCRC incidence risk, with a 2.35-fold risk increase (95% CI, 1.63 to 3.38) in the lowest group compared with the highest. The adjusted hazard ratio for PCCRC associated with 1% increase in ADR was 0.96 (95% CI, 0.95 to 0.98). Among other limitations, the results may not be generalizable to different FIT brands and cutoffs, as well as differences in FIT interval rounds, the study authors noted. “Future cost-effectiveness analyses are warranted to determine an optimal ADR value,” they wrote. “Increasing ADR value does, however, significantly reduce the risk of incident PCCRC.”