Differential response of triple-negative breast cancer to a docetaxel and carboplatin-based neoadjuvant treatment

Abstract

Background: In this study, the authors evaluated whether a pathologic complete response (pCR) or a clinical complete response (cCR) to neoadjuvant treatment in patients with locally advanced breast cancer differed among the 3 subtypes of breast cancer: triple-negative breast cancer (TNBC), human epidermal growth factor receptor 2 (HER2)-positive breast cancer, and hormone receptor-positive/HER2-negative breast cancer. Whether a cCR or a pCR was correlated with fewer recurrences and better survival also was investigated.

Methods: Patients with stage II/III breast cancer received 4 cycles of neoadjuvant docetaxel and carboplatin (TC) every 3 weeks. Patients with HER2-positive tumors were randomized to receive either additional weekly trastuzumab preoperatively or TC alone. Postoperatively, all patients received 4 cycles of TC, and all HER2-positive patients received a total of 52 weeks of trastuzumab. The recurrence-free survival (RFS) and overall survival (OS) rates at 2 years were reported.

Results: Seventy-four patients were enrolled, including 11 patients with TNBC, 30 patients with HER2-positive tumors, and 33 patients with hormone receptor-positive/HER2-negative tumor. The cCR rates were 45.4%, 50% and 40.6% in TNBC, HER2-positive, and hormone receptor-positive/HER2-negative groups, respectively. The pCR rate for the entire group was 26.8%, and patients with TNBC had the best response (54.6%) followed by patients with HER2-positive tumors (24.1%) and patients with hormone receptor-positive/HER2-negative tumors (19.4%; P = .0126). The pCR rate for patients with HER2-positive tumors improved from 7% to 40% if trastuzumab was added (P = .08). Infiltrating ductal cancer, TNBC, negative estrogen receptor and/or progesterone receptor status, tumor classification predicted a pCR (P ≤ .05). Multivariate analysis using a logistic regression test indicated that tumor type was an independent predictor. The RFS rate for patients who did versus patients who did not achieve a pCR was 93.8% versus 78.4% at 2 years, respectively, and 83.3% versus 58% at 3 years, respectively (P = .1227); whereas, for patients who did versus patients who did not achieve a cCR, the RFS rate was 80.9% versus 83.9%, respectively, at 2 years and 65% versus 64.3%, respectively, at 3 years (P = .999).

Conclusions: The current results indicated that the TC combination is promising for the treatment of TNBC. The addition of trastuzumab to TC improved the pCR rate significantly in patients with HER2-positive breast cancer.