Estimating Sensitivity from Tandem Colonoscopy Meta-analyses

Tandem colonoscopy meta-analyses estimate adenoma miss rates, which have been used as a proxy for colonoscopy sensitivity. Doing so overstates sensitivity because it ignores lesions missed by both exams.

We introduce Bayesian and frequentist approaches to estimate white-light colonoscopy (WLC) sensitivity from tandem colonoscopy meta-analyses. Neither approach assumes that the second colonoscopy is perfect. We apply both approaches to reanalyze data from a recent tandem colonoscopy meta-analysis, overall and across ten subgroups. Sensitivity analyses assess how assumptions about the relative performance of enhanced colonoscopy versus WLC affect estimates.

Under our Baseline specification, overall WLC sensitivity estimated by the Bayesian model was 0.54 [0.41, 0.63] (posterior mean and 95% credible interval). Sensitivity rose with lesion size: 0.49 [0.35, 0.60] for 1-5 mm adenomas, 0.64 [0.43, 0.78] for 6-9 mm adenomas and 0.84 [0.70, 0.93] for lesions 10 mm or larger. The frequentist plausible range encompassed the Bayesian estimate. The model-implied miss rate (0.35 [0.30, 0.40]) matched the original meta-analysis estimate and was stable across prior specifications. Assuming enhanced colonoscopy was perfect overstated overall sensitivity by 0.12 [0.06, 0.20].

Tandem colonoscopy data identify the miss rate but not WLC sensitivity, so estimates depend on an external assumption about the relative performance of enhanced colonoscopy versus WLC. As a result, WLC sensitivity estimates varied with the prior specification, especially for small and flat adenomas.

WLC sensitivity may be meaningfully lower than previously assumed in CRC screening cost-effectiveness analyses. Modelers should use colonoscopy sensitivity estimates that do not assume a second colonoscopy exam is perfect.