Extended Benefit from Sequential Administration of Docetaxel after Standard Fluorouracil, Epirubicin, and Cyclophosphamide Regimen for Node-Positive Breast Cancer: The 8-Year Follow-Up Results of the UNICANCER-PACS01 Trial

Abstract

Abstract Purpose. The initial report from the Programme Action Concertée Sein (PACS) PACS01 trial demonstrated a benefit at 5 years for disease-free survival (DFS) and overall survival (OS) rates with the sequential administration of docetaxel after FEC100 (fluorouracil 500 mg/m2, epirubicin 100 mg/m2, and cyclophosphamide 500 mg/m2) for patients with node-positive, operable breast cancer. We evaluate here the impact of this regimen at 8 years. Patients and Methods. Between June 1997 and March 2000, a total of 1,999 patients (age <65) with localized, resectable, non-pretreated, unilateral breast cancer were randomly assigned to receive either standard FEC100 for 6 cycles or 3 cycles of FEC100 followed by 3 cycles of 100 mg/m2 docetaxel (FEC-D), both given every 21 days. Radiotherapy was mandatory after conservative surgery and tamoxifen was given for 5 years to hormone receptor (HR)-positive patients. Five-year DFS was the trial's main endpoint. Updated 8-year survival data are presented. Results. With a median follow-up of 92.8 months, 639 patients experienced at least one event. A total number of 383 deaths were registered. Eight-year DFS rates were 65.8% with FEC alone and 70.2% with FEC-D. OS rates at 8 years were 78% with FEC alone and 83.2% with FEC-D. Cox regression analysis adjusted for age and number of positive nodes showed a 15% reduction in the relative risk of relapse and a 25% reduction in the relative risk of death in favor of FEC-D. Significant relative risk reductions were observed in the HR-positive, HER2-positive, and Ki67 ≥20% subpopulations. Conclusion. Benefits for DFS and OS rates with the sequential FEC-D regimen are fully confirmed at 8 years.