Primary Docetaxel Chemotherapy in Patients with Breast Cancer: Impact on Response and Survival

Primary chemotherapy achieves high clinical response rates and facilitates breast conservation in many patients with large and locally advanced breast cancer. It may also serve to indicate responsiveness to chemotherapeutic agents. A pathological complete response to primary chemotherapy is a primary predictor and surrogate marker of long-term outcome, but occurs in only approximately 15% of patients. Docetaxel is of particular interest in this setting. Primary docetaxel chemotherapy has single-agent activity in both dose-dense and traditional schedules, with acceptable tolerability. Furthermore, concomitant docetaxel-anthracycline schedules have shown promise in Phase II trials, achieving clinical overall response rates (ORRs) of 77-96%, pathological complete responses of up to 24%, and breast conservation in up to 89% of patients. Two Phase III studies have shown that pathological complete response is significantly improved with the addition of docetaxel to anthracycline-based therapy versus the latter alone: the Aberdeen study achieved a rate of 34% versus 16%, respectively (p = 0.04), and the NSABP-B27 study a rate of 26% versus 14%, respectively (p < 0.001). The Aberdeen study has suggested that the addition of docetaxel may yield a survival benefit at 5 years (p = 0.04). The Phase II GEPAR-DUO study hints at a benefit for sequential over concomitant docetaxel-based therapy, with improvements in both clinical response (ORR 87% versus 77%, respectively) and pathological complete response (23% versus 12%, respectively). Non-anthracycline docetaxel-based primary regimens have shown early promise. As we continue to define the optimal regimen, a growing body of evidence supports the use of docetaxel in primary chemotherapeutic regimens for breast cancer.