Response-Guided Omission of Anthracycline in Patients with HER2-Positive Early Breast Cancer Treated with Neoadjuvant Taxane and Trastuzumab: 5-Year Follow-Up of Prognostic Study Using Propensity Score Matching

Abstract

Background: De-escalation therapy omitting anthracycline has been generally adopted for patients with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer in the adjuvant setting, but not in the neoadjuvant chemotherapy (NAC) setting. We investigated whether anthracycline can be omitted in HER2-positive early breast cancer patients receiving neoadjuvant taxane plus trastuzumab with clinical response. Methods: HER2-positive primary breast cancer patients treated using NAC containing trastuzumab were enrolled between September 2006 and July 2018 at Osaka Breast Clinic. The primary outcome was disease-free survival (DFS). The secondary outcome was overall survival (OS). We investigated survival with or without fluorouracil, epirubicin, and cyclophosphamide (FEC) using the log-rank test and propensity score matching (PSM). Results: In total, 142 patients were retrospectively included and median follow-up was 61 months. There was no significant difference in DFS (p = 0.93) and OS (p = 0.46) between the FEC-omitted group and the FEC-added group. The 5-year DFS was 91% and 88% and OS was 100% and 100%, respectively. After PSM, the FEC-omitted group and the FEC-added group had no significant differences in DFS (p = 0.459) and there were no death events in either group. The 5-year DFS was 90% and 88% and OS was 100% and 100%, respectively. Conclusions: Using PSM, the 5-year DFS of HER2-positive early breast cancer was not different with or without anthracycline. Response-guided omission of anthracycline may be an option for HER2-positive early breast cancer patients receiving neoadjuvant taxane and trastuzumab with good response in order to avoid overtreatment.