Detection of adenoma, serrated lesion, and colorectal cancer in Lynch syndrome: a systematic review and meta-analysis.

Colorectal neoplasia outcomes in Lynch syndrome are heterogeneous and limited by inconsistently reported quality metrics, while benchmarks for neoplasia detection rates remain undefined. This systematic review and meta-analysis evaluated neoplasia detection rates in Lynch syndrome and assessed demographic, genotype, and risk factors for neoplasia development. We searched MEDLINE, EMBASE, classic+EMBASE, Cochrane Library, and ClinicalTrials.gov to February 2025 for studies reporting colorectal neoplasia detection rates in Lynch syndrome. The primary outcomes were pooled detection rates for adenoma (ADR), advanced adenoma (AADR), serrated lesion (SLDR), and colorectal cancer (CRCDR). Subgroup analyses were performed to evaluate risk factors and the impact of colonoscopy quality. 36 studies were included, comprising 45 421 colonoscopies in 15 227 Lynch syndrome carriers. Pooled detection rates were: ADR 23.3% (95%CI 20.6-26.3), AADR 5.3% (95%CI 4.5-6.3), SLDR 8.6% (95%CI 6.3-11.7), and CRCDR 2.5% (95%CI 1.9-3.3), with higher proximal ADR (16.4% vs. 11.9% distal) and increased proportion of flat adenomas (flat ADR 16.1%). Completion and bowel preparation data were available for 16 647 (36.7%) and 13 637 (30.0%) procedures, respectively. ADR was highest among trial populations excluding poor-quality or incomplete procedures (30.7%), followed by prospective (24.0%) and retrospective observational studies (18.5%). Advanced neoplasia rates were higher among MLH1/MSH2 than MSH6/PMS2 carriers: MLH1 (AADR 5.1%, CRCDR 5.1%) and MSH2/EPCAM (AADR 6.3%, CRCDR 4.7%) versus MSH6 (AADR 3.5%, CRCDR 3.1) and PMS2 (AADR 4.1%, CRCDR 4.2%). This study characterized neoplasia detection in Lynch syndrome and confirmed higher detection rates with high-quality procedures, supporting the need to benchmark quality standards and neoplasia detection outcomes.