Colonoscopic cancer detection rate: a new performance measure - is it FIT for purpose?

Introduction: Gastrointestinal symptoms correlate poorly with cancer diagnosis. A faecal immunochemical test (FIT) result of ≥10 µg has high sensitivity and negative predictive value for colorectal cancer (CRC) detection. An FIT-based diagnostic pathway may lead to more effective resource utilisation. We aimed to use National Endoscopy Database (NED) data to create a new colonoscopy performance measure, cancer detection rate (CDR) to assess the appropriate identification of target populations for colonoscopy; then to use CDR to assess the impact of implementing an FIT-based referral pathway locally. Methods: NED data were analysed to compare local diagnostic colonoscopic CDR in 2019 (prepathway revision) and 2021 (postpathway revision), benchmarked against overall national CDR for the same time frames. Results: 1, 123, 624 NED diagnostic colonoscopies were analysed. Locally, there was a significant increase in CDR between 2019 and 2021, from 3.01% (2.45%-3.47%) to 4.32% (3.69%-4.95%), p=0.003. The CDR increase was due to both a 10% increase in the number of CRCs detected and a 25% reduction in the number of diagnostic colonoscopies performed. Nationally, there was a smaller, but significant, increase in CDR from 2.02% (1.99%-2.07%) to 2.33% (2.29%-2.37%), p<0.001. The rate of increase in CDR% between 2019 and 2021 was significantly different locally compared with nationally. Conclusion: Our study indicates that the introduction of a robustly vetted FIT-based algorithm to determine whether diagnostic colonoscopy is required, is effective in increasing the colonoscopic CDR. Moreover, CDR appears to be a meaningful performance metric that can be automatically calculated through NED, enabling monitoring of the quality of referral and vetting pathways.