Anthracycline-free or short-term regimen as adjuvant chemotherapy for operable breast cancer: A phase III randomized non-inferiority trial

Background De-escalating anthracycline is gaining popularity for breast cancer patients. We aim to evaluate the non-inferiority of an anthracycline-free or short-term regimen to the standard anthracycline-based regimen for operable patients with human epidermal growth factor receptor 2 (HER2)-negative breast cancer. Methods It is a prospective, open-label, phase 3, randomized non-inferiority trial from June 1, 2010 to June 1, 2017. Follow-up had been kept until July 2019. This trial was conducted at Fudan University Shanghai Cancer Center. Patients with pT1–3N+ or pT2–3N0 but high-risk (grade II/III, lymphovascular invasion, ≤35 years of age or hormone-receptor negative) HER2-negative operable breast cancer were eligible and stratified by age, pathological tumour stage, pathological node status and hormone-receptor status. Patients were randomized to 6 cycles of docetaxel and cyclophosphamide (TC, n = 524), 3 cycles of cyclophosphamide/epirubicin/fluorouracil followed by 3 cycles of docetaxel (CEF-T, n = 523) or epirubicin and cyclophosphamide for 4 cycles followed by paclitaxel for 12 weeks (EC-P, n = 524) as the intention-to-treat population. Of these patients, 94% completed allocated therapy. Difference in disease-free survival (DFS) compared to EC-P. The prespecified non-inferiority margin was 4.5%, corresponding to the hazard ratio (HR) of 1.44 (one-sided α = 0.05), with an assumed 5-year DFS of 89% for EC-P. Findings Included in the intention-to-treat population were 1571 patients (median [IQR] age, 50 [45–57] years; 92% estrogen receptor [ER]-positive; 59% pN+). Through a median follow-up of 5.5 years, HR for TC versus EC-P was 1.05 (5-year DFS: 85.0% vs. 85.9%; 90% confidence interval [CI]: 0.79–1.39, non-inferior P = 0.048) and for CEF-T versus EC-P, 0.99 (5-year DFS: 85.1% vs. 85.9%; 90% CI: 0.75–1.30, non-inferior P = 0.045). Grade 3 or 4 adverse events for TC included rash (3.9%) and peripheral neuropathy (2.8%) and for CEF-T and EC-P diarrhea and nausea/vomiting were predominant. Results of per-protocol analyses were similar. Interpretation Both TC and CEF-T are non-inferior adjuvant regimen to EC-P mainly in patients with ER+HER2- breast cancer. TC is a safe regimen that avoids anthracycline-related side effects.