Benefit of the addition of hormone therapy to neoadjuvant anthracycline-based chemotherapy for breast cancer: comparison of predicted and observed pCR

INTRODUCTION: Neoadjuvant hormonal therapy is generally considered a valid option for hormone receptor positive breast cancer (BC) patients who are unfit for chemotherapy or surgery. AIMS: Whilst numerous studies analyzed efficacy of neoadjuvant chemotherapy (CT) or endocrine therapy (HT) alone in hormone receptor positive patients, there is a lack of research looking at the usefulness of a preoperative combinatorial approach of CT and HT in this patient subgroup. METHODS: Using a predictive model previously described in the literature, developed to analyze the probability of benefit from preoperative chemotherapy, we were able to compare pathological complete response (pCR) rates expected with the use of CT alone with the pCR rates reported in a population of 192 patients treated with the combination of tamoxifen plus anthracycline-based CT at Cremona Hospital between 2003 and 2006. RESULTS: Even with a relatively small patient population, this approach provided insightful information for the selection of hormone receptor positive BC patients most likely to benefit from the use of preoperative HT and CT in combination. Whilst no statistically significant benefit was obtained with the addition of tamoxifen to neoadjuvant chemotherapy in the entire population, or in any of the molecular stratification subgroups, the analysis of the calibration curve showed that a combinatorial approach may improve pCR in patients with luminal B tumors. More specific trials should be designed to confirm our initial results. CONCLUSION: To the best of our knowledge, this is the first report investigating the efficacy of the combination of CT and HT in the neoadjuvant treatment of hormone receptor positive BC.