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Clinical Performance of Original and Revised Bethesda Guidelines for the Identification of MSH2/MLH1 Gene Carriers in Patients with Newly Diagnosed Colorectal Cancer: Proposal of a New and Simpler Set of Recommendations

2006; Lippincott Williams & Wilkins; Volume: 101; Issue: 5 Linguagem: Inglês

10.1111/j.1572-0241.2006.00522.x

1572-0241

Francisco Rodríguez‐Moranta, Antoni Castells, Montserrat Andreu, Virgı́nia Piñol, Sergi Castellvı́-Bel, Cristina Alenda, Xavier Llor, Rosa M. Xicola, Rodrigo Jover, Artemio Payá, Xavier Bessa, Francesc Balaguer, Joaquín Cubiella, Lídia Argüello, Juan Diego Morillas, Luís Bujanda,

Colorectal Cancer Treatments and Studies

Identification of individuals who should undergo hereditary nonpolyposis colorectal cancer (HNPCC) genetic testing is a critical and difficult issue. For this purpose, the National Cancer Institute outlined a set of recommendations, the Bethesda guidelines, which have recently been revised. OBJECTIVE To compare the clinical performance of original and revised Bethesda guidelines for the detection of MSH2/MLH1 gene carriers in patients with colorectal cancer. METHODS A total of 1,222 patients with newly diagnosed colorectal cancer were included in the EPICOLON study, a prospective, multicenter, nationwide epidemiology survey aimed at establishing the incidence of HNPCC in Spain (JAMA 2005; 293:1986–1994). Performance characteristics of the original and revised Bethesda guidelines were assessed with respect to the presence of MSH2/MLH1 germline mutations. Logistic regression analysis was performed to establish the most effective strategy. RESULTS Original or revised Bethesda guidelines were equivalent strategies in terms of sensitivity (100%vs 100%; ns), specificity (98.1%vs 97.9%; ns), and overall accuracy (98.1%vs 97.9%; ns), as well as positive (25.8%vs 24.2%) and negative predictive values (100%vs 100%). The most discriminating individual variables were criteria number 1 (i.e., fulfillment of the Amsterdam criteria; RR = 34.14; 95% CI = 6.85–170.16; p < 0.001) and number 2 (i.e., individuals with two HNPCC-related neoplasms; RR = 35.63; 95% CI = 4.83–262.6; p < 0.001) of the original guidelines, and criterion number 1 of the revised guidelines (i.e., colorectal cancer diagnosed under 50 yr of age; RR = 29.34; 95% CI = 3.81–225.96; p= 0.001). The aggregation of these three criteria was equivalent to both Bethesda guidelines in terms of sensitivity (100%) and negative predictive value (100%), but superior to the revised criteria regarding specificity (98.5%; p < 0.05), overall accuracy (98.5%; p < 0.05), and positive predictive value (30.8%). CONCLUSIONS Original and revised Bethesda guidelines are equivalent, highly effective criteria for the identification of MSH2/MLH1 gene mutation carriers in patients with newly diagnosed colorectal cancer. A new set of recommendations, based on a combination of some of their individual criteria, may provide additional advantages in terms of effectiveness.