Breast Conservation After Neoadjuvant Chemotherapy For Triple-Negative Breast Cancer: Surgical Results From An International Randomized Trial (Brightness)

514Background: Neoadjuvant systemic therapy (NST) increases the frequency of breast-conserving therapy (BCT) in stage II-III breast cancer, but there is little data on how often it converts patients (pts) from BCT-ineligible (BCT-I) to BCT-eligible (BCT-E) and on the impact of other factors on surgical choices. We collected surgical assessment and management data from an international randomized trial of NST in triple-negative breast cancer (TNBC). Methods: Women with operable TNBC were randomized to veliparib (V) with carboplatin (C) and paclitaxel (P), placebo with C and P or placebo with P followed by doxorubicin and cyclophosphamide. The surgeons assessed BCT candidacy by clinico-radiographic criteria before and after NST; surgical management was at surgeon and patient discretion. We assessed interactions between BCT eligibility pre- and post-NST, germline BRCA mutation (gBRCA) status, continent of treatment and achievement of pathologic complete response(pCR) and percentage of pts who underwent BCT v...