666 Sentinel lymph node biopsy after neoadjuvant chemotherapy in node positive patients with breast carcinoma: We need to improve

Introduction/Background* False negative rate (FNR) of SNLB in breast cancer patients who are node positive prior to Neoadjuvant chemotherapy (NAC) can be improved by removing more than two sentinel nodes. Our objective was to analyse identification rate (IR) and false negatives rates (FNR) in these patients according to the number of sentinel nodes (SN) removed. Methodology A retrospective cohort study was performed from October 2012 to December 2018. Patients with invasive breast cancer, who were clinical node positive at diagnosis, underwent sentinel node lymph biopsy (SLNB) and axillary lymph node dissection after NAC. Pathological analysis of SN was stained by haematoxylin and eosin and immunohistochemistry or by one-step nucleic acid amplification. SN was considered positive if any residual disease was detected. IR was defined as the number of patients with successful identification of SN. False negative was considered when there was residual disease in axillary lymph node dissection and SN was negative. Result(s)* A total of 112 patients with invasive breast cancer and clinical proven node involvement at diagnosis were included. IR of SNLB was 94,6% and FNR was 15.4%. Removing at least three sentinel nodes, FNR decreased to 10%. At least three SN were obtained in 56 patients (50,8%). Conclusion* : IR is adequate but FNR is high. Removing three or more SN decreases FNR from 16 to fewer than 10% in clinically node-positive breast cancer patients who undergo NAC. This approach would benefit half of patients. Other approaches should be taken for axillary lymph node staging after NAC.