Characteristics of response to neoadjuvant chemotherapy in patients with aggressive biological subtypes of stage II-III breast cancer. Original study

Goal: To analyze the tumor response to NACT in patients with aggressive biological subtypes of stage II-III breast cancer based on the contemporary scoring systems for residual pathological stage evaluation and the residual cancer burden according to the RCB system. Materials and methods: A total of 172 women with stage II-III breast cancer of aggressive biological subtypes (triple negative in 34,3 %; HER2-positive tumors in 28,5 %; luminal B Her2-negative BC in 37,2 %) were included in this analysis. The median age of the patients was 47 years (24-81 years); cT2 was the predominant tumor size (65,1 %); 69,8 % of patients had regional lymph node involvement; 62,8 % of patients had G3 tumor; Ki67 ≥ 30 % was found in 90,7 % of cases. All patients received neoadjuvant chemotherapy (NACT) with concomitant anti-HER2 blockade in case of HER2-positive tumors followed by surgery. Morphological assessment included evaluation of the residual pathological stage and the residual cancer burden according to the RCB system. Results: Total pathological complete response (no evidence of residual invasive tumor in the breast and lymph nodes - tpCR) was observed in 69 of 172 patients (40,1 %), which corresponded to the ypT0N0 pathological stage and RCB class 0. The highest tpCR rate was achieved in patients with HER2-positive cancer (63 % in non-luminal HER2-positive subtype and 59.1 % in luminal HER2 + BC) and triple negative cancer (50,8 %). Meanwhile, the tpCR rate in patients with luminal HER2-negative BC was only 15,6 %, p function show_eabstract() { $('#eabstract1').hide(); $('#eabstract2').show(); $('#eabstract_expand').hide(); }