Purpose: Preoperative (neoadjuvant) chemotherapy for operable breast cancer downstages tumors initially not suitable for breast-conserving surgery. A pathologic complete response (pCR) to neoadjuvant chemotherapy may be a surrogate for longer overall survival, but this beneficial effect remains to be established. This phase III trial evaluated whether doubling the number of cycles of neoadjuvant treatment increased the pCR rate.
Patients and methods: Patients with biopsy-proven breast cancer (T1-4a-c, N+/-, M0; stage I to III) were eligible and randomly assigned to either three or six cycles of epirubicin 75 mg/m2 and docetaxel 75 mg/m2 on day 1 and granulocyte colony-stimulating factor on days 3 through 10 (ED+G), every 21 days. The primary end point was the pCR rate of the breast tumor. Secondary end points were pathologic nodal status after surgery and the rate of breast-conserving surgery.
Results: A total of 292 patients were accrued, and 288 patients were assessable for efficacy and safety. Groups were well balanced for known prognostic factors. Six cycles of ED+G, compared with three cycles, resulted in a significantly higher pCR rate (18.6% v 7.7%, respectively; P = .0045), a higher percentage of patients with negative axillary status (56.6% v 42.8%, respectively; P = .02), and a trend towards more breast-conserving surgery (75.9% v 66.9%, respectively; P = .10). Rates of adverse events were similar, and no patients died on treatment.
Conclusion: Doubling the number of neoadjuvant ED+G cycles from three to six results in higher rates of pCR and negative axillary nodal status with no excess of adverse effects. Thus, six cycles of ED+G should be the standard neoadjuvant treatment for operable breast cancer if this combination is chosen.