Adjuvant Cyclophosphamide and Docetaxel With or Without Epirubicin for Early TOP2A-Normal Breast Cancer: DBCG...

Purpose Administration of anthracycline and taxane therapy in the adjuvant setting is considered a standard for breast cancer. We evaluated a non-anthracycline-based regimen in TOP2A-normal patients. Patients and Methods In this multicenter, open-label, phase III trial, 2,012 women with early TOP2A-normal breast cancer and at least one high-risk factor were randomly assigned to receive six cycles of docetaxel (75 mg/m²) and cyclophosphamide (600 mg/m²) every 3 weeks (DC) or three cycles of epirubicin (90 mg/m²) and cyclophosphamide (600 mg/m²) followed by three cycles of docetaxel (100 mg/m²; EC-D). The primary end point was disease-free survival (DFS) after a median of 5 years of follow-up. Secondary end points were patient-reported toxicity, overall survival (OS), and distant disease-free survival. Results At a median estimated potential follow-up of 69 months, 5-year DFS was 87.9% (95% CI, 85.6% to 89.8%) in the EC-D arm and 88.3% (95% CI, 86.1% to 90.1%) in the DC arm. There was no significant difference in the risk of DFS events (hazard ratio [HR], 1.00; 95% CI, 0.78 to 1.28; P = 1.00), distant disease-free survival (HR, 1.12; 95% CI, 0.86 to 1.47; P = .40), or mortality (HR, 1.15; 95% CI, 0.83 to 1.59; P = .41) in the intent-to-treat analysis. A significant interaction between menopausal status and treatment group was observed for DFS ( P = .04) but not for OS ( P = .07). Patients with grade 3 tumors derived most benefit from DC, and patients with grade 1 to 2 tumors derived most benefit from EC-D (DFS: interaction P = .02; and OS: interaction P = .03). Patients receiving EC-D reported significantly more stomatitis, myalgia or arthralgia, vomiting, nausea, fatigue, and peripheral neuropathy, whereas edema was more frequent after DC. Conclusion This study provides evidence to support no overall outcome benefit from adjuvant anthracyclines in patients with early TOP2A-normal breast cancer.