Emily L. Albright, Mary C. Schroeder, Kendra Foster, Sonia L. Sugg, Lillian M. Erdahl, Ronald J. Weigel, Ingrid M. Lizarraga

High-volume single-institution studies support the oncologic safety of nipple sparing mastectomy (NSM). Concerns remain regarding the increased potential for complications, recurrence, and delays to subsequent adjuvant therapy. A national database was used to examine treatment and outcomes for NSM patients. Women undergoing unilateral NSM or skin sparing mastectomy (SSM) for stage 0-4 breast cancer from 2004 to 2013 were identified from the National Cancer Database. Demographic and oncologic characteristics, short-term outcomes and time to local and systemic treatment were compared. NSM was performed on 8173 patients: 8.7% were node positive, and for stage 1-4 disease, 10.6% were triple negative (TN) and 15.3% were HER2-positive. NSM patients were less likely than SSM patients to receive chemotherapy [CT] (37.4 vs. 43.4%) or radiation [PMRT] (15.6 vs. 16.9%), and were also more likely to present with clinically early-stage disease. NSM patients with high-risk features were more likely to receive CT in the neoadjuvant [NCT] than adjuvant setting [AC] (OR 3.76, 1.81, and 1.99 for clinical N2/3, TN, and HER2-positive disease, all p < 0.001). On multivariate analysis, NSM patients had a higher rate of pathologic complete response [pCR] (OR 1.41, p < 0.001). Readmission rate, positive margin rate and time to CT, PMRT or hormonal therapy were not increased for NSM compared to SSM patients. Over one third of NSM patients received chemotherapy and/or radiation. NSM patients with high-risk features were more likely to receive NAC and obtain a pCR. NSM patients did not experience worse outcomes or delayed adjuvant therapy compared to SSM.