Efficacy of neoadjuvant therapy with trastuzumab concurrent with anthracycline- and nonanthracycline-based regimens for HER2-positive breast cancer.

Abstract

532 Background: To evaluate the pathologic complete response (pCR) rates and relapse-free survival (RFS) and overall survival (OS) of patients receiving neoadjuvant systemic therapy (NST) with trastuzumab in combination with an anthracycline- or a nonanthracycline-based regimen. Methods: We reviewed records of 300 patients with HER2-positive breast cancer treated with either sequential paclitaxel and trastuzumab and FEC75 in combination with trastuzumab (PH-FECH) or docetaxel, carboplatin, and trastuzumab (TCH). The Kaplan-Meier product-limit method was used to estimate RFS and OS rates. Logistic regression models and Cox proportional hazards models were fit to determine the associations between NST, pCR, and survival. Results: pCR rates were 60.6% and 43.3% for patients who received PH-FECH (n=235) and TCH (n=65), respectively (p=0.016). Patients who received PH-FECH were 1.45 times more likely to have a pCR (Odds ratio [OR]:1.45; 95% confidence interval (CI):1.06-1.98; P=0.02). At a median follow-up of 26.8 months for survivors, there were 28 recurrences and 15 deaths. Three-year RFS rates were 93% and 71% (P<0.001), and 3-year OS rates were 96% and 86% (p=0.008) for patients who received PH-FECH and TCH, respectively. Patients who received PH-FECH had a lower risk of recurrence (hazard ratio [HR]:0.27; 95% CI:0.12-0.60; p=0.001) and death (HR:0.37; 95% CI:0.12-1.13; p=0.08) than those treated with TCH. Conclusions: The type of NST in HER2-positive breast cancer is predictive of pCR rate independent of disease and patient characteristics. While TCH is active, trastuzumab combined with a taxane and then with an anthracycline (PH-FECH) shows a higher pCR rate and a RFS advantage.