Abstract P3-01-17: Evaluation of “Systematic sonographic axillary staging” on clinically node positive breast cancer patients becoming clinically node negative after neoadjuvant chemotherapy

Abstract

Abstract Purpose Accumulating evidence supports usage of sentinel lymph node biopsy (SLNB) for clinically node positive (cN+) breast cancer (BC) patients, who become clinically node negative (ycN-) after neoadjuvant chemotherapy (NAC). How to reassess the axilla after NAC is a challenging issue. In our institution, Systematic Sonographic Axillary Staging (SSAS) is currently being tested in this group of patients. The aim of this study is to analyze the early results of this approach. Method During initial presentation, systematic sonographic axillary staging is done preferentially by the surgeon. Needle biopsy is then performed of suspicious node(s). At completion of NAC, the axilla is again systematically staged sonographically, taking into account the pre-treatment disease locations. Any residual morphologically suspicious node undergoes a repeat needle biopsy. According to the evidence of residual disease, the patient is either scheduled for axillary dissection (AD) or for SLNB. We analyzed early results of SSAS on patients, who converted ycN (-) after NAC. Strictly adherence to SSAS protocol was the only inclusion criteria. Results A total of 25 patients were included. On repeat axillary USG after NAC, 11 patients had normal appearing and 14 patients had suspicious appearing lymph nodes (LNs). 14 patients underwent repeat biopsy; 9 patients had benign and 5 patients had malign pathology results. 20 patients underwent SLNB. Among 20 patients, 12 patients had negative SLNB and 8 patients had positive SLNB (4 patients had benign appearing LNs on repeat USG and 4 patients had benign biopsy results). 13 patients underwent AD (8 patients after positive SLNB and 5 patients directly after positive US-guided biopsy result). Among 8 patients with positive SLNB, 4 patients had macrometastatic disease (>2mm) on SLNB. In 3 of these 8 patients, no additional disease was found on AD, while 1 patient had only isolated tumor cell and 1 patient had only micrometastasis (Table 1). Table 1. Size of the axillary involvement among patients with positive SLNB Sentinel Lymph Node BiopsyAxillary DissectionPatient #LN* (+) / Total LNs removedSize of involvement (mm)LN* (+) / Total LNs removedSize of involvement (mm)11/611/50.122/42.50/5-31/363/19141/210/3-51/11.50/21-62/21.53/32.573/357/10384/447/133* LN = lymph node Conclusion Systematic sonographic axillary staging is a reliable approach to cN (+) patients, who become ycN0 after NAC. This observation should be tested in a larger study. Citation Format: Ozmen T, Lazaro M, Vinyard A, Avisar E. Evaluation of “Systematic sonographic axillary staging” on clinically node positive breast cancer patients becoming clinically node negative after neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-01-17.