Clinical Advantages of Neoadjuvant Docetaxel (T) and Carboplatin (C) ± Trastuzumab (H) in Locally Advanced Breast Cancer (LABC).

Abstract

Abstract Background: Neoadjuvant systemic treatment has become a standard choice for locally advanced breast cancer with many proposed benefits in achieving clear margins, preserving breasts, reducing relapse and improving survival. Recently, we completed a neoadjuvant trial studying the effects of 4 cycles of docetaxel (75 mg/m2) and carboplatin (AUC=6) with or without trastuzumab (4mg/kg loading dose and 2 mg/kg weekly dose) on LABC. In this report, we assessed whether clinical complete response (cCR) or pathologic complete response (pCR) correlated better with having breast conservation surgery, fewer relapses and improved survival outcomes.Materials and Methods: Seventy-one of the 74 consented patients with T2-T4 non-metastatic breast cancer completed the preoperative treatment and had evaluable data on tumor response, surgical treatment and clinical outcome. We used the Kaplan Meier method to estimate survival probabilities and log rank test to compare relapse-free and survival curves.Results: Clinical outcomes from a preplanned 2-year analysis of a phase II neoadjuvant are reported. Of the 19 patients with pCR, 16 occurred in patients with cCR (n=32) and 3 were in the group of non-cCR (n=39). Although cCR overestimated tumor response, 84.2% pCR occurred in the cCR group and only 15.8% in the non-cCR group. The relapse-free survival at 2 and 3 years for pCR vs. non-pCR were 93.8% and 83.3% vs. 78.4% (p=0.122) and 58%, respectively; and for cCR vs. non-cCR were 80.9% and 65% vs. 83.9% and 64.3% (p=0.999). The pCR was also more predictive than cCR for overall survival. Of the 30 HER2 positive breast cancer, 15 received trastuzumab throughout the neoadjuvant and adjuvant phases for a total of 52 weeks. The remaining 15 patients received identical chemotherapy but trastuzumab was started after the surgery and continued for 52 weeks. While distinctively different pCR between the two treatment groups was expected, the better survival rate observed in the group receiving neoadjuvant TCH was not expected. Our study showed that pCR was strongly associated with a more frequent use of lumpectomy than the non-pCR group 63.2% vs. 36.5% (p=0.045).Conclusion: The effects of preoperative systemic treatment on LABC can be assessed both clinically and pathologically. Our data suggests that pathologic complete response was a better predictor for having breast conservation surgery and relapse-free survival rates. Our data also suggests that patients with HER2 positive breast cancer may benefit from receiving preoperative trastuzumab and chemotherapy. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1100.