Colorectal Cancer Stage Distribution at First and Repeat Fecal Immunochemical Test Screening

BACKGROUND & AIMS: For colorectal cancer (CRC) screening to be effective, it is important that screen-detected cancers are found at an early stage. Studies on stage distribution of screen-detected CRC at repeat screening of large population-based fecal immunochemical test (FIT)-based screening programs and the impact of FIT cut-off values on staging currently are lacking. METHODS: We obtained data for FIT-positive participants (FIT cut-off, 47 mg hemoglobin/g feces) at their first or second (ie, repeat) screening from the Dutch National Screening Database from 2014 to 2018. Tumor characteristics were acquired through linkage with The Netherlands Cancer Registry. We compared stage at diagnosis (I-II vs III-IV) of CRCs detected at a first or second screening. In addition, we analyzed the hypothetical yield and stage distribution of CRC for different FIT cut-off values up to 250 mg hemoglobin/g feces. RESULTS: At the first and second screenings, respectively, 15,755 and 3304 CRCs were detected. CRCs detected at the first or second screening were equally likely to be stages I to II (66.5% vs 67.7%; relative risk, 1.02; 95% CI, 1.00-1.05). A hypothetical increase of the FIT cut-off value from 47mg to 250 mg resulted in a reduction of detected CRCs by 88.3% and 79.0% at the first or second screening, respectively. Even then, the majority of detected CRCs (63%-64%) still would be diagnosed at stages I to II.CONCLUSIONS: FIT-based screening is effective in downstaging CRC, and also at repeat screening. Increasingly, the FIT cut-off level has a limited impact on the stage distribution of detected CRCs, although it greatly affects CRC detection and thus is important to keep low.