Long-term survival analysis of addition of carboplatin to neoadjuvant chemotherapy in HER2-negative breast cancer.

Abstract

Addition of carboplatin (CBDCA) to neoadjuvant chemotherapy (NAC) in triple-negative breast cancer (TNBC) has improved pathological complete response (pCR) rates in previous studies. We present long-term survival outcomes (disease-free survival [DFS], pre-planned secondary endpoint; overall survival [OS], post hoc exploratory endpoint) of our randomized study of the addition of CBDCA to NAC for HER2-negative breast cancer. Patients with stage II/III, HER2-negative breast cancer (N = 179) were randomly assigned to receive CP-CEF (four 3-week cycles of CBDCA [area under the curve, 5mg/mL/min, day 1] and weekly paclitaxel [wPTX, 80mg/m2, day 1, 8, 15] followed by four 3-week cycles of cyclophosphamide, epirubicin, and 5-fluorouracil [CEF, 500/100/500mg/m2]) or P-CEF (four cycles of wPTX followed by four cycles of CEF) as NAC. DFS and OS were analyzed at each population of pCR status and assigned treatment arm. Of 179 patients, 154 were available for long-term follow-up. At a median follow-up of 6.6years (range, 0.7-8.0years), patients who achieved pCR [n = 42, 23.5% (CP-CEF: n = 28, P-CEF: n = 16)] had longer DFS and OS than non-pCR patients [DFS; HR 0.15 (0.04-0.61), P = 0.008, OS; log-rank P = 0.003]. Addition of carboplatin to NAC significantly improved DFS and OS in the subset of patients with TNBC [DFS: HR, 0.22 (0.06-0.82), P = 0.015; OS: HR, 0.12 (0.01-0.96), P = 0.046], but not in the subset of patients with hormone receptor-positive disease or among all patients. Addition of carboplatin to neoadjuvant chemotherapy significantly improved DFS and OS in patients with TNBC but not in those with hormone receptor-positive, HER2-negative breast cancer.