Oncology/Women's Health
Session # P2-02-07
Synchronous or metachronous breast primaries are a well-known indication of hereditary breast cancer, particularly within BRCA1/2 mutation carriers. However, the frequency of gene mutations within this patient group has not been well defined, especially in the setting of multi-gene panel testing (MGPT). We conducted a retrospective review of mutation carrier status in a population of females with breast cancer(s), but no other reported cancer diagnoses, and who had MGPT at a single diagnostic laboratory. Among 31,864 females tested, the following were excluded from analysis: 5389 (17%) had variants of unknown significance (VUS), 133 (0.4%) had moderate risk mutations and 316 (1.0%) had MUTYH monoallelic mutations. For the remaining 26,026 females, we evaluated whether mutation status is associated with risk of multiple breast primaries using Fisher’s exact test and logistic regression analysis adjusting for age at testing, age at first breast cancer diagnosis, and mutations in other genes. The number of genes analyzed ranged from 5-49, depending on the panel ordered. Gene-specific analyses were limited to with 10 or more mutations in this cohort (ATM, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CDKN2A, CHEK2, MRE11A, MUTYH, MSH6,