Correlation between adenoma detection rate in colonoscopy- and fecal immunochemical testing-based colorectal cancer screening programs

Background: The adenoma detection rate (ADR) is the main quality indicator of colonoscopy. The ADR recommended in fecal immunochemical testing (FIT)-based colorectal cancer screening programs is unknown. Methods: Using the COLONPREV (NCT00906997) study dataset, we performed a post-hoc analysis to determine if there was a correlation between the ADR in primary and work-up colonoscopy, and the equivalent figure to the minimal 20% ADR recommended. Colonoscopy was performed in 5722 individuals: 5059 as primary strategy and 663 after a positive FIT result (OC-Sensor (TM); cut-off level 15 mu g/g of feces). We developed a predictive model based on a multivariable lineal regression analysis including confounding variables. Results: The median ADR was 31% (range, 14%-51%) in the colonoscopy group and 55% (range, 21%-83%) in the FIT group. There was a positive correlation in the ADR between primary and work-up colonoscopy (Pearson's coefficient 0.716; p<0.001). ADR in the FIT group was independently related to ADR in the colonoscopy group: regression coefficient for colonoscopy ADR, 0.71 (p=0.009); sex, 0.09 (p=0.09); age, 0.3 (p=0.5); and region 0.00 (p=0.9). The equivalent figure to the 20% ADR was 45% (95% confidence interval, 35%-56%). Conclusions: ADR in primary and work-up colonoscopy of a FIT-positive result are positively and significantly correlated.