Sentinel lymph node biopsy following neoadjuvant chemotherapy in clinically node-negative breast cancer patients.

Abstract

15 Background: Sentinel lymph node biopsy (SLNB) is a widely accepted staging method for patients with early breast cancer. But SLNB following neoadjuvant chemotherapy (NAC) is also controversial because of insufficient evidence to recommend as a standard procedure. The aim of our study was to demonstrate the feasibility of SNLB following NAC. Methods: The clinical study of SLNB for clinically node-negative breast cancer patient was conducted as a large cohort study to confirm the identification rate and safety of this procedure. It was investigated by The Japanese Breast Cancer Society and was accomplished between the years March 2008 and October 2009. In this study 11,228 cases are registered before SLNB from 64 institutions. Of the 11,228 eligible cases, analysis was conducted among 489 cases that were introduced neoadjuvant chemotherapy. Results: SLNB was performed in 110 cases before NAC, 379 cases after NAC. The sentinel node identification rate before NAC was 106/110 cases (96.4%), after NAC was 373/379 cases (98.4%). Intraoperative frozen section analysis was performed in 280 cases, 71 cases were positive. The remaining 219 patients displayed no metastasis in the intraoperative examination, and 6 of these 219 (2.7%) were positive in the final pathological analysis. Conclusions: The identification rate of SLNB following NAC is not inferior to the result of major clinical studies previously reported in the world. There is insufficient evidence to recommend this as a standard procedure. Further research with subgroup analysis is necessary to identify whether SLNB following NAC is feasible or not (planned study). The primary end point for Group A is local relapse rate, Group B is not only the accuracy and false negative rate also the utility of One-step Nucleic Acid Amplification (OSNA).