Abstract P3-20-08: Does contralateral prophylactic mastectomy improve survival in triple negative breast cancer?

Background: Despite increased incidence of contralateral prophylactic mastectomy (CPM), there is insufficient evidence that it improves survival in women at average risk for breast cancer. In addition to BRCA1/2 mutation carriers, patients with estrogen-receptor negative tumors have been examined as a subgroup that may seek to benefit from CPM. In this study, we sought to investigate whether CPM improves survival in patients with triple negative breast cancer (TNBC).Study Design: Survival outcomes were evaluated for all TNBC patients from a multi-institutional database from 1999-2018 at New York Presbyterian - Weill Cornell Medical Center and Henry Ford Health System. Median follow-up time was 44.4 months.Results: 802 TNBC patients were evaluated. The median age was 57 years. 17% patients underwent CPM. Factors associated with CPM were White American race, younger age, presence of lymphovascular invasion (LVI), lack of mammography screen-detection, mastectomy surgery, postoperative adjuvant radiotherapy, and having had genetic testing. A borderline significant trend was observed in improved overall survival among patients undergoing CPM versus those not having CPM (5-year OS 95.1% vs. 85.0%; p = 0.05). Subset analysis of patients younger than 50 years of age at diagnosis demonstrated no improvement in overall survival for patients undergoing CPM versus those that declined CPM (94.3% v. 88.7%; p = 0.21). Conclusion: Our data demonstrate a trend in improved 5-year overall survival in TNBC patients undergoing CPM. However, in patients younger than 50 years at diagnosis, CPM did not confer a survival advantage. Citation Format: Genevieve A Fasano, Solange Bayard, Yalei Chen, Jennifer Marti, Rache Simmons, Alexander Swistel, Jessica Bensenhaver, S David Nathanson, Lindsay Petersen, Erica Proctor, Melissa Davis, Lisa Newman. Does contralateral prophylactic mastectomy improve survival in triple negative breast cancer? [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-20-08.