Neoadjuvant chemotherapy in operable breast cancer with docetaxel, doxorubicin, and cyclophosphamide (TAC) or TAC followed by vinorelbine and capecitabine (NX): Final results and analysis of markers predicting response to treatment

Abstract

524 Background: The aim of this analysis was to determine the pathological complete remission rate (pCR) for the entire Gepartrio study population and to identify markers predicting response to NACT. Methods: The design of the Gepartrio study was described elsewhere (von Minckwitz et al.). Age at diagnosis, tumor size, lymph node status, estrogen (ER), progesterone (PgR), HER-2 status, histological type, and grade were assessed in uni- and multivariate analysis. Clinical response after 2 cycles TAC and pCR at surgery were used as efficacy endpoints. Results: 2072 pts were randomized depending on response after 2 cycles TAC. 1122 pts (54.2%) had a clinical response after 2 cycles and 385 (18.6 %) pCR. The highest pCR rate (60%) was observed in pts with triple neg tumors and < 40 years. In the HR pos/HER-2 pos pts the pCR rates were 17.6% vs. 9% for HR pos/HER-2 neg pts (p<0.001). In the HR neg subset absence of HER-2 overexpression (“triple neg tumors”) resulted in significantly improved pCR rates compared to the HR neg HER-2 pos subset (40.7% versus 31.6%, p=0.041). In univariate analysis predictors for both an early response and a pCR at surgery were age < 40 years, non T4 tumor, grade 3, neg hormone receptors (HR) and a triple neg status. Non lobular histology was only predictive for a pCR in univariate analysis. In multivariate analysis independent factors for early response were non T4 tu, tumors ≥ 40 mm, poor grading and neg HRs. Independent predictors for a pCR remained age < 40 years, poor grading, a non lobular subtype and triple neg tumors. Conclusions: The pCR rate for the whole study population of the Gepartrio trial was comparable to other neoadjuvant regimens. Markers identified as independent predictors may help in decision making for pts being considered for neoadjuvant chemotherapy. [Table: see text]