Sentinel Lymph Node Biopsy Alone after Neoadjuvant Chemotherapy in Patients with Initial Cytology-Proven Axillary Node Metastasis

PURPOSE: Neoadjuvant chemotherapy (NAC) has been recently used to downstage breast cancer. However, in patients with initial axillary lymph node (ALN) metastasis, ALN dissection regardless of the NAC response remains the standard treatment. The purpose of this study was to identify the feasibility and accuracy of sentinel lymph node biopsy (SLNB) after NAC in patients with ALN metastasis at diagnosis. METHODS: From January 2007 to August 2013, data of patients who were diagnosed with invasive breast cancer and ALN metastasis and treated with NAC followed by definitive surgery in two centers were collected retrospectively. A total of 386 patients were enrolled and classified into five groups according to surgical procedure for the ALNs and pathologic results. RESULTS: At SLNB after NAC, sentinel lymph nodes (SLNs) that stained blue or were hot, including suspicious nodes, were identified; the SLN identification and false-negative rates was 96% and 10%, respectively. There was no difference in the overall survival among the groups. For patients who revealed a pathologic complete node response, there was a significant difference in the disease-free survival rate between the SLNB only and complete ALN dissection groups (p=0.031). However, the rate of axillary recurrence demonstrated no significant differences among the groups (p>0.050). CONCLUSION: SLNB after NAC in breast cancer patients with initial ALN metastasis may help identify downstaging to negative nodal status and thereby reduce the surgical morbidity by avoiding standard ALN dissection.