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.

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.

[Evaluation of therapeutic regimens for taxane-resistant recurrent/metastatic breast cancer].

Taxanes (TX) were administered to 246 of 292 patients with recurrent/metastatic breast cancer (MBC) who were treated in Hiei Hospital between January 2001 and May 2006. Recently, TX has been increasingly prescribed for preoperative treatment and postoperative adjuvant therapy. To improve the prognosis of MBC, regimens effective for TX-resistant cancer patients should be developed. In this study, with respect to hormone receptor (HR) and Her 2/neu (HER 2), we retrospectively investigated whether our series responded to the regimens used after TX resistance was acquired. As post TX-resistance therapy (trastuzumab was combined in HER2-positive patients), 387 treatment regimens were administered to 166 patients. The following regimens achieved a response rate (patients achieving PR or CR/patients who could be evaluated) of 10% or more: combination therapy with TX and capecitabine (11/61, 18%), CPT-11 (10/57, 17.5%), vinorelbine (5/46, 10.9%), MFL-P (continuous treatment with MTX, 5-FU, LV, and CDDP) (12/47, 25.5%), and DMpC (5'-DFUR, MPA, CPA p.o.) (5/16, 31.2%). The latter 2 regimens achieved a high response rate,and some HR (-) and HER 2 (-) patients also responded to these regimens. In HR (+) or HER 2 (+) patients who responded to TX, survival was longer than that of non-responders. However, there was no difference in the treatment responsiveness of post-TX regimens between TX-responders and non-responders, suggesting the survival-prolonging effect of TX.