Factors Affecting Pathological Complete Response After Neoadjuvant Chemotherapy in Operable Primary Breast Cancer

Objective: To investigate factors influencing pathological response to neoadjuvant chemotherapy (NAC) in operable primary breast cancer. Study Design: Descriptive study. Place and Duration of Study: Breast Center, Shunyi District Health Care Hospital for Women and Children of Beijing, Beijing 101300, P.R. China, from January 2009 to December 2017. Methodology: Two hundred and sixty-one operable primary invasive breast cancer patients treated with NAC were included in this observational study. Pathological complete response (pCR) was defined as no residual invasive disease in either the breast or the axillary lymph nodes, with non-invasive breast residuals permitted (ypTO/is ypNO). Factors affecting pCR were subjected to univariate and multivariate analysis. Results: Seventy-six patients (29.1%) achieved pCR after NAC. Tumor size, histological grade, status of estrogen receptor (ER) and progesterone receptor (PgR), expression of human epidermal growth factor receptor 2 (HER2) and Ki67, axillary lymph node status, and chemotherapy regimen were all significantly associated with pCR in univariate analysis (all p<0.05). In multivariate analysis, high histological grade, negative HR status and lymph nodes, positive HER2 status, and taxane-based regimens were independent predictive factors of pCR. Patients with HER2-positive tumors were more sensitive to NAC regimen including trastuzumab. Conclusion: In this study, breast cancer patients with high histological grade, negative HR status and lymph nodes, positive HER2 status, as well as taxane-based regimens were significantly associated with achieving pCR with NAC.