Assessment of pathological complete response (pCR) to neoadjuvant dose-dense chemotherapy in HER2+ patients with locally advanced breast cancer (LABC) treated with trastuzumab (T) compared with HER2+ and HER2- patients treated without T

Abstract

11057 Purpose: To identify Her2+expression as predictive factor for pCR to T in pts with LABC treated with neoadjuvant chemotherapy. Methods: A total of 127 newly diagnosed stage II-III, including inflammatory tumors, breast cancer pts were reviewed. Median age was 47,7 (r 26,4 - 73,6). Median tumor size was 5 cm (1–10). 57 (44,8%) were T2, 33 (26%) T3 and 37 (29,2%) T4 (25 of them inflammatory). 59 (46,5%) pts were clinically lymph node positive before treatment. 50 pts (39,4%) were hormonal receptor negative, and 38 (30,4%) Her2+. The pts received one of the 2 chemotherapy regimens every 2 weeks with prophylactic growth factors support: A) epirubicin 90 mg/m2-cyclophophamide 600 mg/m2 d1 for 3 cycles, followed by a second sequence with paclitaxel (P) 150 mg/m2- gemcitabine (G) 2500 mg/m2 d1 ± T 2mg/kg/wk according to status Her2 (n= 73); B) adriamicin 40mg/m2 d1 plus P 150mg/m2-G 2000 mg/m2 d2 for 6 cycles (n=54). Subsequently pats underwent surgery and radiotherapy and/or adjuvant hormonal therapy according to institutional practice. Results: 43 (33,9 %) pts achieved a pCR (absence of invasive tumor in the breast). The pts were classified in two groups to analyze the influence of the treatment with T on pCR: (1) Her2+ pats treated with T (20 pts): pCR 50%; (2) The rest of the pts, treated only with chemotherapy (107 pts: 18 Her2+ and 89 Her2- ): pCR 32% (p=0.068). Breast-conserving surgery was performed in 77 pts (60,6%). Conclusions: Both dose dense chemotherapy regimens were highly effective in terms of pCR. Although there were not a significative correlation of Her2+ status and trastuzumab therapy with pCR, probably due to the small number of pts, a favorable tendency was seen in the group of Her2+ tumors treated with T. At the meeting, analysis of the correlation of pCR with progression free survival will be presented. No significant financial relationships to disclose.