Neoadjuvant platinum-based chemotherapy (CT) for triple-negative locally advanced breast cancer (LABC): Retrospective analysis of 125 patients

Abstract

625 Background: Triple-negative breast cancer (TNBC), defined by lack of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2, accounts for 15–20% of all breast cancers and is associated with poor prognosis. There is no consensus regarding optimal CT for treatment of such patients. Preclinical data suggests TNBC may be sensitive to platinums because of deficiencies in BRCA-associated DNA repair. The aim of this study was to evaluate pathologic complete response (pCR) and overall survival (OS) in patients with TNBC treated with neoadjuvant platinum-based CT. Methods: We identified 674 patients with LABC who received neoadjuvant CT between January 1999 and June 2008 at University of Miami. Of these, 125 (18.5%) had histopathologic confirmation of TNBC. All patients received neoadjuvant platinum salts + docetaxel. 76 (61%) also received neoadjuvant AC, while 42 (34%) received adjuvant AC. pCR was defined as no residual invasive disease in breast and axilla. OS was calculated according to Kaplan-Meier. Results: Demographics: median age 50 (28–86 years). 60% premenopausal. TNM stage distribution: T1 0.9%, T2 5.2%, T3 53.4%, T4 40.5%, N0 25.0%, N1 36.2%, N2 35.4%, N3 3.4%, M0 100%, inflammatory 11%, median tumor size = 9.5 cm. Follow up duration ranged from 0.3 to 8.9 years. pCR was observed in 42 of 125 patients (34%; 95% CI 26–43%). Among patients receiving neoadjuvant AC, 30 of 76 (40%; 95% CI 28–51%) had pCR, while amongst those receiving adjuvant AC, 12 of 42 (29%, 95% CI 16–45%) had pCR at the time of definitive surgery. Patients achieving pCR had significantly higher OS (5-yr rate = 73% in pCR, vs. 49% in non-pCR; p < 0.001). OS in TNBC patients receiving cisplatin/docetaxel was significantly superior to those receiving carboplatin/docetaxel (11 mortality events out of 78 patients receiving cisplatin based CT vs 24 out of 47 receiving carboplatin based CT logrank p = 0.001). Conclusions: To date, this is the largest single institution cohort of locally advanced TNBC uniformly treated with platinum+docetaxel-based CT regimens. Platinum/docetaxel-based neoadjuvant CT provided high rates of pCR and excellent OS for women with locally advanced TNBC. No significant financial relationships to disclose.