Magnitude, Risk Factors, and Factors Associated With Adenoma Miss Rate of Tandem Colonoscopy: A Systematic Review and Meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of tandem colonoscopy studies
PubMed 30738046 · doi:10.1053/j.gastro.2019.01.260
What was done
A systematic review and meta-analysis of PubMed, Web of Science, and Ovid EMBASE through April 2018 was conducted to evaluate tandem colonoscopy studies. The primary outcomes were pooled adenoma miss rate (AMR) and advanced adenoma miss rate (AAMR). Secondary outcomes assessed miss rates across anatomical locations, lesion size, morphology, histology, and patient populations, with meta-regression applied to identify associated quality factors.
What was found
Across 43 publications and over 15,000 tandem colonoscopies, pooled miss rates were 26% (95% CI: 23%–30%) for adenomas, 9% (95% CI: 4%–16%) for advanced adenomas, and 27% (95% CI: 16%–40%) for serrated polyps. Miss rates were elevated for flat adenomas (34%; 95% CI: 24%–45%), patients at high colorectal cancer risk (33%; 95% CI: 26%–41%), and proximal advanced adenomas (14%; 95% CI: 5%–26%). Adenoma detection rate (ADR), adenomas per index colonoscopy, and adenomas per positive index colonoscopy (APPC) correlated independently with AMR (P = .02, P = .01, and P = .008, respectively). APPC was the only independent factor associated with AAMR (P = .006); an APPC ≥ 1.7 yielded an AAMR of 2% versus 35% for APPC < 1.7 (P = .0005).
Why it matters
Colonoscopy fails to detect roughly one in four adenomas and one in eleven advanced adenomas in tandem evaluations. The findings indicate that APPC may serve as a valuable complementary quality metric beyond conventional ADR for monitoring mucosal inspection thoroughness.
Limits
The abstract does not report individual study designs (such as same vs. different endoscopist tandem passes), risk of publication bias, or patient-level clinical outcome data such as post-colonoscopy colorectal cancer rates. The proposed APPC thresholds require prospective validation across routine clinical settings.
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