Randomized Clinical Trial of Adjuvant Fluorouracil, Epirubicin, and Cyclophosphamide Chemotherapy for Patients With Fast-Proliferating, Node-Negative Breast Cancer

Abstract

PURPOSE: The prospective applicability of new biologic tumor information to personalize adjuvant treatment of women with operable breast cancer remains to be demonstrated. The aim of the present study was to investigate whether patients with fast-proliferating, node-negative breast cancer could benefit from adjuvant chemotherapy with fluorouracil, epirubicin, and cyclophosphamide (FEC). PATIENTS AND METHODS: Beginning in November 1989, we analyzed the proliferative activity of primary tumors in a consecutive series of women with node-negative breast cancer to identify subgroups of patients with a worse prognosis and who were therefore suitable candidates for adjuvant systemic therapy. Proliferative activity was determined by means of the [3H]-thymidine incorporation assay using an autoradiographic technique. Women with fast-proliferating breast cancer ([3H]-thymidine labeling index, > 2.3%) were randomized to receive either six cycles of adjuvant FEC or no adjuvant therapy until disease progression. RESULTS: One-hundred twenty-five and 123 patients treated with radical surgery for pT1 to T2, N0, M0 breast cancer were randomized to the FEC and control arms, respectively. After a median follow-up of 70 months, 27 events (21.6%) were observed in the FEC arm and 39 (32.2%) in the control arm, with a significantly lower number of locoregional relapses in the FEC group. Five-year disease-free survival (DFS) was 81% in the FEC group and 69% in the control group (P < .02 by log-rank test). Cox multivariate analysis described the impact of adjuvant therapy with FEC on DFS as independent of the patients’ main clinical-pathologic characteristics. CONCLUSION: FEC adjuvant polychemotherapy seems able to significantly improve the clinical outcome of patients with fast-proliferating, node-negative breast cancer.