LAUSR

BACKGROUND De-escalation therapy omitting anthracycline has been generally adopted for patients with 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 FEC (fluorouracil, epirubicin and cyclophosphamide) 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.