Phase III Trial Comparing Doxorubicin Plus Cyclophosphamide With Docetaxel Plus Cyclophosphamide As Adjuvant Therapy for Operable Breast Cancer

Abstract

Purpose The combination of doxorubicin and cyclophosphamide (AC) is a standard adjuvant chemotherapy regimen. Studies of docetaxel and cyclophosphamide (TC) in metastatic breast cancer (MBC) showed promise in MBC. In 1997, we initiated a randomized adjuvant trial of TC compared with standard-dose AC with a primary end point of disease-free survival (DFS). Patients and Methods Patients were eligible if they had stage I to III operable invasive breast cancer with complete surgical excision of the primary tumor. Between June 1997 and December 1999, 1,016 patients were randomly assigned to four cycles of either standard-dose AC (60 and 600 mg/m2, respectively; n = 510) or TC (75 and 600 mg/m2, respectively; n = 506), administered intravenously every 3 weeks as adjuvant chemotherapy. Radiation therapy (as indicated) and tamoxifen, for patients with hormone receptor–positive disease, were administered after completion of chemotherapy. Results Both treatment groups (TC and AC) were well balanced with respect to major prognostic factors. Patients were observed through 2005 for a median of 5.5 years. At 5 years, DFS rate was significantly superior for TC compared with AC (86% v 80%, respectively; hazard ratio [HR] = 0.67; 95% CI, 0.50 to 0.94; P = .015). Overall survival rates for TC and AC were 90% and 87%, respectively (HR = 0.76; 95% CI, 0.52 to 1.1; P = .13). More myalgia, arthralgia, edema, and febrile neutropenia occurred on the TC arm; more nausea and vomiting occurred on the AC arm as well as one incident of congestive heart failure. Conclusion At 5 years, TC was associated with a superior DFS and a different toxicity profile compared with AC.