6 vs. 3 cycles of epirubicin/docetaxel + G-CSF in operable breast cancer: results of ABCSG-14

Abstract

553 Background: Preoperative chemotherapiy (PROP) for operable breast cancer is established to downstage tumors primarily not suitable for breast conserving surgery. A pathologic complete response (pCR) after PROP might be a surrogate marker for longer overall survival (OS) but the rates of pCR with current treatment regimens are still rather low and a beneficial effect of PROP upon OS remains to be established. In 1999, the ABCSG set out to test the hypothesis whether prolonging the time of the neoadjuvant treatment period by doubeling the number of cycles of the same drugs might raise the rate of pCR after PROP by converting more partial responses into pCR's. Methods: Patients (pts) with biopsy proven breast cancer T1–4a-c,N+/-,M0 were eligible for this prospectively randomized phase III trial. 282 pts (estimated drop-out rate: 5%) were planned to detect a significant difference (one-sided p < 0,05, Fisher's exact test) with a power of 82%. Pts were randomized to receive either 3 cycles of epirubicin 75mg/m2 and docetaxel 75mg/m2 on day 1 + G-CSF 30 MU days 3–10 q 21 days (ED+G) or 6 cycles of the identical regimen. Primary end point was the rate of pCR. The pathological nodal status and the rate of breast conserving surgical procedures served as secondary end points. Results: 292 pts were accrued to the trial between 6/199 and 12/2002 and 288 pts are eligible. Both trial groups were well balanced for tumor size, clinical nodal status, menopausal status, hormone receptor status, HER2-status, and trial center. The results of the primary and the secondary end points are depicted in the table. There was no significant difference in serious adverse events per patient and per cycle and no patient died while on treatment. Conclusions: Doubeling the number of cycles of neoadjuvant chemotherapy (6 vs. 3 x ED+G) results in significantly higher rates for pCR and negative axillary nodal status with with no excess of side effects. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Aventis