Worldwide prevalence of Lynch syndrome in patients with colorectal cancer: Systematic review and meta-analysis

Purpose: Lynch syndrome (LS) is the most common hereditary colorectal cancer (CRC) syndrome, with an estimated prevalence of 2% to 3% of CRC. A prevalence study is needed to provide accurate estimates of the true prevalence of LS. Methods: MEDLINE (Ovid), Embase, and Web of Science were searched. Prevalence was calculated by random effects meta-analysis models. I2 score was used to assess heterogeneity across studies. Meta-regression was performed for between-study variance. Results: A total of 51 studies were included in this review. The overall pooled yield of LS screening was 2.2% based on all methods of detection. Studies performing germline tests on all participants with CRC reported higher prevalence (5.1%) as opposed to studies only performing germline tests on participants with tumors with mismatch repair deficiency (1.6%) or microsatellite instability (1.1%). Selected cohorts of CRC had a higher prevalence of germline LS diagnoses. Conclusion: LS prevalence across multiple ethnic, geographic, and clinical populations is remarkably similar. Universal germline testing of patients presenting with cancer identifies that most CRCs are attributed to LS. Young patients presenting with CRC and those who fulfill criteria for a familial risk provide the highest returns for LS identification. Our study supports the universal germline CRC screening for LS.