A randomized, multicenter phase III trial comparing doxorubicin + cyclophosphamide followed by paclitaxel or doxorubicin + paclitaxel followed by weekly paclitaxel as adjuvant therapy for high-risk breast cancer

Abstract

517 Background: This study compared the disease-free survival (DFS) obtained with 2 regimens of adjuvant therapy for patients (pts) with high-risk breast cancer Methods: Women PS 0–1 with local, operable, confirmed stage I-III adenocarcinoma were eligible. Pts may have had primary surgery, with no residual tumor. Therapy was as follows:Arm 1 (AC→T) - doxorubicin 60 mg/m2 plus cyclophosphamide 600 mg/m2 repeated every 3 weeks for 4 cycles → paclitaxel 175 mg/m2 repeated every 3 weeks for 4 cycles; Arm 2 (AT→T) - doxorubicin 50 mg/m2 plus paclitaxel 200 mg/m2 repeated every 3 weeks for 4 cycles → paclitaxel 80 mg/m2 weekly ×12. Results: 1,830 pts were enrolled and treated; n=915 Arm 1 (AC→T) and n=915 Arm 2 (AT→T). Pts were: PS=0 (70%/Arm), ER+/PR+ (54% and 50%, Arms 1 and 2 respectively), ER-/PR- (35% and 34%) with 0 positive nodes (N+) (28% and 27%), 1–3 (N+) (44% and 46%), 4–9 (N+) (21% and 18%) and 10+ (N+) (7% and 8.5%). Most were postmenopausal (57%/Arm); median age was 52 years/Arm. To date 1,655 pts (90%) are alive. 5-year DFS was 80% vs 81% for Arms 1 and 2 Overall 5-year survival was 86% vs 89%, in Arms 1 and 2. Cause of death was recurrence for 76 pts in Arm 1 and 56 pts in Arm 2. The main reasons for pts being taken off study treatment were toxicity (85 pts Arm 1 vs 128 pts Arm 2), recurrence (79 pts Arm 1 vs 52 pts Arm 2), and consent withdrawal (18 pts Arm 1 vs 30 pts Arm 2). The most frequent toxicities were neutropenia, leukopenia, neuropathy, febrile neutropenia, nausea, vomiting, arthralgia, and myalgia. GI toxicities were more frequent in Arm 1. Alopecia occurred in both Arms (77%). Conclusions: At 5-years, the AT→T produced significantly better OS (p=0.054) and improved DFS (p=0.19). Clinically important toxicities were more frequent with AC→T. Given this, AT→T in the adjuvant treatment of breast cancer is well tolerated and warranted in place of AC→T in these pts. Research support provided by Bristol-Myers Squibb (Princeton, NJ). No significant financial relationships to disclose.