Associations between BRCA Mutations in High-Risk Breast Cancer Patients and Familial Cancers Other than Breast or Ovary

PURPOSE: We investigated the relationship between BRCA mutations and the distribution of familial cancers other than breast or ovary in high-risk breast cancer patients. METHODS: Patients with breast cancer who had at least one of the following risk factors were enrolled: reported family history of breast or ovarian cancer; 40 years of age or younger age at diagnosis; bilateral breast cancer; or male gender. Genetic testing for BRCA mutation and questionnaires about personal and family histories of malignancies were performed. RESULTS: Among the 238 eligible patients, 49 (20.6%) patients had BRCA1/2 mutations, which were more frequent in patients with multiple risk factors (p<0.0001). There were 271 members of 156 (65.5%) families who had histories of other primary cancer. The distribution of the families was 119 (63.0%) and 37 (75.5%) in the BRCA-negative and positive group, respectively (p=0.0996). Multiple familial cancers occurred in 70 families, which were significantly more frequent in BRCA-positive families (p=0.0034). By ordinal logistic regression, the occurrence of multiple familial cancers was associated with BRCA mutations (p=0.0045), not with other risk factors. The most common site of disease was the stomach, which is the most common in nationwide. And the proportional incidence of pancreatic cancer (6.8%) was significantly higher than that of nationwide cancer statistics (2.4%, p=0.0137). CONCLUSION: BRCA mutations in high-risk breast cancer patients were associated with multiple risk factors and multiple family members with other primary cancers. Genetic counseling based on accurate information should be provided to families with BRCA mutation carriers.