Predictive Factors of Residual Metastatic Axillary Lymph Nodes after Neoadjuvant Chemotherapy in Node-Positive Breast Cancer

ABSTRACT

PURPOSE: Sentinel lymph node biopsy (SLNB) has been a reliable technique in breast cancer staging. However, some authors reported that SLNB after neoadjuvant chemotherapy (NAC) could lead to low identification rates and high false-negative rates. Hence, whether only SLNB can be applied after NAC is controversial. The aim of this study was to identify predictive factors of residual metastatic axillary lymph nodes after NAC. METHODS: In this study, 71 breast cancer patients with clinically positive lymph nodes (cN1), who received axillary lymph node dissection (ALND) after NAC between July 2012 and September 2014, were enrolled. The patients were divided into N1 and N0 groups according to the presence of residual axillary metastatic lymph nodes after ALND. We compared the clinical, radiological, and immunohistological factors between two groups. RESULTS: In the 71 patients with cN1who received NAC, N1 and N0 status were confirmed after surgery in 43 and 28 patients, respectively. The clinical stage at diagnosis was IIA in one patient, IIB in 15 patients, IIIA in 35 patients, IIIB in two patients, IIIC in 10 patients, and IV in eight patients. Most of the patients (n=57) received eight cycles (four cycles of anthracycline and four of taxane) of chemotherapy. Our study showed that the primary tumor was downstaged in 58 of the 71 patients (81.7%). Sixteen patients (22.5%) had pathological complete response (pCR) and 42 (59.2%) had pathological partial response. In a multivariate analysis, tumor response and human epidermal growth factor receptor 2 (HER2) were identified as significant factors. However, no significant differences were observed in the results of postchemotherapy ultrasonography, and pre- or post-positron emission tomography computed tomography (maximum standardized uptake value reduction). CONCLUSION: In the NAC setting, SLNB before ALND is feasible for tumors predicted to have a pCR or if target therapy had been administered for HER2-positive breast cancer.