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Background & Aims: In Latin America, genetic testing for Lynch Syndrome (LS) has been partially implemented. Traditionally, LS diagnosis relied on the Amsterdam criteria and Bethesda guidelines, collectively known as Traditional Screening (TS). However, TS may miss up to 68% of LS cases. To improve detection rates, Universal Tumor Screening (UTS) has been introduced. UTS involves screening all newly diagnosed colorectal cancer (CRC) patients for molecular markers to more effectively identify LS cases., Methods: Clinical and molecular data on 1,684 colorectal cancer (CRC) patients, collected between 1999 and 2020, were provided by 24 Latin American genetic cancer registries and centers. Germline genetic testing was not consistently performed across all cases., Results: LS screening strategies were available for 72% (1,209/1,684) of cases, with germline testing conducted in one-quarter (304/1,209) of these. Most cases (78%, n=943) underwent UTS, primarily in Argentina, Chile, and Uruguay, while 22% (266/1,209) were screened through TS. UTS identified deficient mismatch repair (dMMR) tumors in 29% (272/943) of cases. The rate of LS confirmed by sequencing was higher with UTS (53.3%, 65/122) compared to TS (47.8%, 87/182), though the difference was not statistically significant (P value = 0.175)., Conclusions: UTS is widely implemented in Latin America; however, the low detection rate of LS demonstrated in this study raises concerns about the routine use of germline genetic testing in our region. Our study provides real-world outcomes that highlight disparities in screening uptake and counseling referrals, illustrating the challenges that Latin American countries face in hereditary cancer syndrome screening. These results contribute to the rationale for designing effective screening strategies for LS, which may also be applicable to other hereditary cancer syndromes, ultimately., (Copyright © 2025. Published by Elsevier Inc.)

Colorectal cancer (CRC) is one of the most common cancers in Latin America and the Caribbean, with the highest rates reported for Uruguay, Brazil and Argentina. We provide a global snapshot of the CRC patterns, how screening is performed, and compared/contrasted to the genetic profile of Lynch syndrome (LS) in the region. From the literature, we find that only nine (20%) of the Latin America and the Caribbean countries have developed guidelines for early detection of CRC, and also with a low adherence. We describe a genetic profile of LS, including a total of 2,685 suspected families, where confirmed LS ranged from 8% in Uruguay and Argentina to 60% in Peru. Among confirmed LS, path_MLH1 variants were most commonly identified in Peru (82%), Mexico (80%), Chile (60%), and path_MSH2/EPCAM variants were most frequently identified in Colombia (80%) and Argentina (47%). Path_MSH6 and path_PMS2 variants were less common, but they showed important presence in Brazil (15%) and Chile (10%), respectively. Important differences exist at identifying LS families in Latin American countries, where the spectrum of path_MLH1 and path_MSH2 variants are those most frequently identified. Our findings have an impact on the evaluation of the patients and their relatives at risk for LS, derived from the gene affected. Although the awareness of hereditary cancer and genetic testing has improved in the last decade, it is remains deficient, with 39%-80% of the families not being identified for LS among those who actually met both the clinical criteria for LS and showed MMR deficiency., (© 2018 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)