Abstract P2-14-06: Characterization of Risk Factors in Breast Cancer Young Adult Patients

Abstract Background: Breast cancer diagnosis in the age group of 20-34 years represents 4% of breast cancer cases diagnosed at all ages in São Paulo state, Brazil. Risk factors in this age group of patients are little understood, especially in those not reporting familial history of breast/ovarian cancer syndrome (BOCS). Identification of predisposing factors and BRCA1/2 mutations (mut) in young Brazilian patients may contribute to characterize women with increased risk of breast cancer. Objective: Characterize familial history and risk factors for breast cancer in young adult Brazilian patients and germline mutations in BRCA1/2 genes. Methodology: Forty-five patients diagnosed with breast cancer at ages 18-35 years were interviewed using a comprehensive questionnaire. Genomic DNA was extracted from peripheral blood and BRCA1/2 mut were screened by Sanger sequencing of coding sequences, analyzed through Mutation Surveyor v.3.20 and searched in BIC Database, LOVD, LOVD-IARC and UMD. Results: Mean age of patients at time of diagnosis was 33 y (24-35y); mean age of menarche was 13 y (8-19y); 32 (71.1%) patients had at least one born child, median age of first pregnancy was 22 years; 86.7% never smoked; 71.1% were no regular alcoholic drinkers; mean of body mass index was 27.14 (overweight). Most patients were diagnosed with invasive ductal carcinoma (91.1%); grades II or III (95.5%); ER/PR positive (57.8%); triple-negative (TN: 31.1%) or HER2 positive (17.8%). Among them, 22.2% reported positive familial history (NCCN criteria for BOCS). Deleterious mutation in BRCA1/2 genes was found in 17.8% of the patients (BRCA1, n = 3; BRCA2, n = 5). Among 10 and 35 patients reporting or not BOCS familial history, 3 (30%) and 5 (14.3%) respectively, had BRCA1/2mut. All BRCA1mut patients had TN tumors; BRCA2mut patients had ER/PR positive (60%), HER2 positive (20%) or TN tumors (20%). Most patients reported one or two of the following risk factors: early menarche (<12y); current/previous use of oral contraceptive; no breast feeding and no parities. Among 30 patients reporting no familial history and presenting BRCA1/2 wild type, six (20%) and four (13.3%) reported three or four of these risk factors, respectively. Considering breast cancer protective factors, 17.8% of the patients breast fed >16 months and 24.4% were aged <20y at birth of first child. Diet habits are being analyzed. Conclusion: In young adults with breast cancer there is a trend towards a higher rate of positive familial history among whom there is a trend towards a higher chance of BRCA1/2 mutation. A better characterization of patients reporting no familial history is urgently needed. Financial Support: FAPESP. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-14-06.