Abstract P5-22-22: Breast tumor location in BRCA mutation carriers and implications for prevention

Abstract

Abstract Introduction: Close to 65% of BRCA mutation carriers do not choose prophylactic mastectomy, despite their high breast cancer risk. Breast reduction mammoplasty is a surgical technique shown to reduce breast cancer risk and can be modified to target specific areas of the breast. We wondered if a majority of tumors in BRCA mutation carriers would be confined to one quadrant, allowing for the use of targeted cosmetic mammoplasty as a novel method of risk reduction. Methods: We reviewed imaging reports on 103 consecutive patients with BRCA mutations and invasive breast cancer, and categorized tumor location by quadrant. Tumors spanning >1 quadrant were classified as being in both. Bilateral cancers were counted separately. Categorical variables were compared with the chi-squaredtest. Results: Mean age at breast cancer diagnosis was 44 years with mean tumor size of 2.2 cm (0.1-7cm). 92% of tumors were invasive ductal carcinoma, 46% were hormone receptor positive, 10% Her2 positive, and 44% triple negative. 70% of the tumors were unicentric. Tumors were significantly more likely to be in the upper outer quadrant whether or not multicentric tumors were included in the analysis (p<0.00001). Her2 positive tumors were more likely to be multicentric than other subtypes (p=0.021). Conclusions: More than half of breast cancers in BRCA mutation carriers form in the upper outer quadrant, suggesting that removing this quadrant through breast reduction mammoplasty could significantly reduce breast cancer risk. For women who are not ready for prophylactic mastectomy, this data supports an intermediate risk reduction step instead of only offering surveillance. Citation Format: Hosseini A, Esserman LJ, Wallace AM, Au A, Mukhtar RA. Breast tumor location in BRCA mutation carriers and implications for prevention [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-22-22.