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

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.

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.

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.

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.