Purpose: This study was designed to determine the effect of adding docetaxel (T) to preoperative doxorubicin and cyclophosphamide (AC) on breast cancer response rates and disease-free survival (DFS) and overall survival (OS).
Patients and methods: Women with operable breast cancer (N = 2,411) were randomly assigned to receive preoperative AC followed by surgery, AC followed by T and surgery, or AC followed by surgery and then T. Tamoxifen was initiated concurrently with chemotherapy. Median time on study for 2,404 patients with follow-up was 77.9 months.
Results: Addition of T to AC did not significantly impact DFS or OS. There were trends toward improved DFS with addition of T. The addition of T reduced the incidence of local recurrences as first events (P = .0034). Preoperative T, but not postoperative T, significantly improved DFS in patients who had a clinical partial response after AC (hazard ratio [HR] = 0.71; 95% CI, 0.55 to 0.91; P = .007). Pathologic complete response, which was doubled by addition of preoperative T, was a significant predictor of OS regardless of treatment (HR = 0.33; 95% CI, 0.23 to 0.47; P < .0001). Pathologic nodal status after chemotherapy was a significant predictor of OS (P < .0001).
Conclusion: The addition of preoperative or postoperative T after preoperative AC did not significantly affect OS, slightly improved DFS, and decreased the incidence of local recurrences. The sample size of this study was not sufficient to yield significance for the moderate DFS improvement. Concurrent use of tamoxifen may have limited the impact of adding T.