A randomized study comparing docetaxel/cyclophosphamide (TC), 5-fluorouracil/epirubicin/cyclophosphamide (FEC) followed by TC, and TC followed by FEC for patients with hormone receptor-positive HER2-negative primary breast cancer

PURPOSE: Our primary objective was to determine the benefit/risk of anthracycline-free regimens by comparing docetaxel + cyclophosphamide (TC) alone, fluorouracil + epirubicin + cyclophosphamide (FEC) followed by TC, or TC followed by FEC as a primary treatment for patients with HR-positive, HER2-negative BC. METHODS: We randomized patients with stage I–III HR-positive HER2-negative, operable BC to receive either six cycles of TC (TC6), three cycles of FEC followed by three cycles of TC (FEC-TC), or three cycles of TC followed by three cycles of FEC (TC-FEC). The primary endpoint was the pathological response. Secondary endpoints included clinical response, type of surgical procedure, recurrence, death, and adverse events (by NCI-Common Terminology Criteria for Adverse Events v.3.0). We conducted all statistical analyses using SAS Version 9.2. RESULTS: We enrolled 195 patients and analyzed data from 193 as the intention-to-treat population. Pathological complete response rates were numerically higher in the TC6 group than in the other groups (p = 0.321). The breast conservation rate was significantly higher in the TC6 group (73%) than in the other groups (FEC-TC 51%, TC-FEC 45%, p = 0.007). Adverse events with grade > 3 were not common in the treatment groups (p = 0.569). The overall and distant disease-free survivals were similar among the groups with median follow-up of 5.80 years. CONCLUSIONS: Despite similar long-term efficacy and safety profile, the higher breast conservation rate in the TC6 group suggests that preoperative chemotherapy without an anthracycline may benefit patients with HR-positive HER2-negative BC. TRIAL REGISTRATION: UMIN000003283 https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000003873. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s10549-020-05590-w) contains supplementary material, which is available to authorized users.