Prevalence of germline mutations in BRCA1/2 in patients from northeastern Brazil.

Abstract

e13603 Background: Identifying carriers of hereditary cancer predisposition syndromes (HCPS) improves prevention and treatment. However, due to the elevated cost of genetic testing, information on the prevalence and incidence of HCPS is scarce, depriving patients of assertive treatment―a scenario observed worldwide, especially in regions like Northeastern Brazil. In this study, we determined the prevalence of hereditary breast and ovarian cancer (HBOC) in patients from Ceará (Brazil) based on NCCN criteria. Methods: The patients (n = 267) were evaluated using NGS gene panels, while retrospective data were analyzed statistically with the chi-squared test, Fisher’s test and multinomial logistic regressions ( p< 0.05; SPSS 20.0). Results: BRCA1/2 was detected in 21.3% (57/267) of the sample, but BRCA1 was more prevalent than BRCA2 (70%; 40/57 vs 30%; 17/57) ( p< 0.001). Having two or more primary tumors ( p= 0.031) or primary ovarian cancer ( p= 0.029) was associated with the pathogenic mutation BRCA1/2. The latter was detected in patients with bilateral tumors (40%) and male breast cancer (45%), and in patients under 45 years (67%), with familial breast cancer (27%) and familial ovarian cancer (41%). In the multivariate analysis, the triple-negative phenotype was strongly associated with mutated BRCA1/2 ( p= 0.003). Conclusions: The prevalence of HBOC in our sample is compatible with rates reported worldwide. The study variables (bilaterality, male sex, age < 45 years, family history of breast or ovarian cancer, and triple-negative phenotype) reinforce the diagnostic criteria published by the NCCN.