Efficacy of dose-dense versus standard neoadjuvant chemotherapy regimensin luminal HER2-negative breast cancer: Interim results of single-centre study

Abstract

Introduction. The efficacy of dose-dense AC in adjuvant chemotherapy of luminal breast cancer (ER+ BC) compared with the standard dosing regimen followed by switching to taxanes has been proven in numerous clinical trials and in a large meta-analysis of the EBCTCG group. However, no study about efficiency of this regimen in neoadjuvant setting has been published.The aim of the study. To assess the effectiveness of dose-dense regimens of neoadjuvant chemotherapy (NAC) of ER + HER2-BC (4 AC once every 2 weeks (dose dense, ddAC), then 4 courses of Docetaxel once every 3 weeks or 12 weekly injections of Paclitaxel [4D/12P]) and their comparison with the standard ones (AC once every 3 weeks [ACq3w], hereinafter 4D/12P). Primary end points are complete response rate (pCR) and RCB0–I.Methods. This retrospective study included patients with resectable or locally advanced luminal HER2-negative breast cancer who received NAC from Janu 2017 to Aug 2022. Statistical hypothesis – the dose-dense regimen AC increases the frequency of RCB0–I from 22 to 32% compared to the standard dosing regimen with subsequent switching to taxanes, with a study power of 80%, ά = 0.05, 138 patients should be included in the study. A total of 315 patients were included in the study, of which 147 and 168 patients received dose-dense (ddAC) and standard chemotherapy (ACq3w), respectively. After propensity matching analysis 138 patients in each group were included in the final analysis.Results. The pCR rate was 18.84% in the ddAC group versus 14.49% in the AC q3w group, the differences were not statistically significant (p = 0.379). The frequency of RCB0–I was higher in the ddAC – group 33.33% versus 21.74% in the AC q3w (p = 0.040). According to the subgroup analysis, rate of RCB0–I was significantly higher in patients younger 50 years, cN0, with the expression of progesterone receptors in ≥ 20%.Conclusions. This is the first study to compare the efficacy of a ddAC NAC with a standard regimen for ER + HER2-BC. NAC with ddAC is associated with an increase in RCB0–I rate.