Role of proliferation in response to neoadjuvant chemotherapy in GEICAM/2006-03 and GEICAM/2006-14 breast cancer patients.

10616 Background: Ki67 proliferation biomarker determined by immunohistochemistry (IHC) has been studied as a prognostic and predictive factor in Operable Breast Cancer (OBC). Ki67 modifications after neoadjuvant endocrine therapy have been correlated with long term outcome. However, there is no robust data about its predictive role in Neoadjuvant Chemotherapy (NC). In this study, we investigated Ki67 value as predictor of NC efficacy. Methods: 193 patients (pts) from 2 GEICAM phase II randomized trials (2006-03 and 2006-14) were included: 78 (40%) received epirubicine plus cyclophosphamide followed by docetaxel (EC-D), 41 (21%) EC-D plus carboplatin, and out of the 74 HER2+ pts, 37 (19%) received EC-D plus tratuzumab and 37 (19%) EC-D plus lapatinib. Median age was 49 years. From series, 87% were invasive ductal carcinoma, 58% premenopausal, 50% grade III, 23% luminal , 39% basal and 38% HER2+. Ki67 was centrally assessed by IHC (MIB1 clone) and median score was 40% (range 1-100%). Pathological Complete ...