DOSE-RESPONSE RELATIONSHIP OF EPIRUBICIN-BASED 1ST-LINE CHEMOTHERAPY FOR ADVANCED BREAST-CANCER - A PROSPECTIVE RANDOMIZED TRIAL

Purpose: We compared prospectively the antitumor efficacy of two combination chemotherapy regimens with two different dose levels of epirubicin as first-line treatment for advanced breast cancer. Patients and Methods: One hundred forty-one fully assessable patients were randomized to receive either our intensified schedule (group A, n = 71) of epirubicin 50 mg/m2 on days 1 and 8 (every 3 weeks), or a non-intensified program (group B, n = 70) in which epirubicin was only administered on day 1. Both groups also received fluorouracil (5 FU) and cyclophosphamide 500 mg/ m2 on day 1 of each course. Results: A statistically significant difference in response rate was observed (69% in group A v 41% in group B, P < .001) for both locally advanced (LA) and recurrent metastatic (RM) disease. Response duration (22 v 14 months, P < .01) and time to progression (TTP; 19 v 8 months, P < .02) were also significantly improved. Overall survival was similar in both groups. However, univariate and/or multivariate analyses showed a meaningful relationship between type of treatment allocated, dose-intensity (DI) of epirubicin, and response rate, as well as between TTP and survival. Ultimately, TTP and survival were also influenced by further treatment modalities, namely, hormonotherapy and chemotherapy. Conclusion: This study validates prospectively the concept of a dose-response relationship for an anthracycline-based chemotherapy in previously untreated advanced breast cancer. © 1993 by American Society of Clinical Oncology.