Abstract P2-14-19: Targeted Axillary Lymph Node Dissections Using Radar Reflector Localization Can Reduce Unnecessary Axillary Lymph Node Dissections in Node Positive Patients Treated with Neoadjuvant Chemotherapy

Abstract

Abstract Background Targeted axillary dissection (TAD) is a surgical strategy that involves staging the axilla through sentinel lymph node biopsy (SLNB) combined with the removal of a biopsy-proven positive lymph node identified by a clip. TAD reduces the false negative rate of SLNB alone in patients with clinically detected nodal metastasis who receive neoadjuvant chemotherapy (NAC) while avoiding axillary lymph node dissections (ALND). Radar reflector-localization (RRL) can be used to identify previously positive nodes and safely and effectively guide dissection. Methods We performed an institutional retrospective chart review of breast cancer patients with clinical stage T1-3 and N1-3 disease treated with NAC from 2015 to 2020 who had a biopsy proven positive node and underwent TAD using RRL. The primary outcome was the retrieval of clipped node as documented by gross visualization or specimen radiography. Secondary outcomes included pathologic complete response rates and completion axillary lymph node dissections (cALND). Results 79 patients were identified who fulfilled inclusion criteria. 32 (40.5%) had RRL markers placed prior to chemotherapy (mean 187 days prior to surgery) and 47 (59.5%) had RRL markers placed following the completion of chemotherapy (mean 7 days prior to surgery). The clipped node was retrieved in 77 patients (97.5%). 32 of the 34 ypN0 (i+) patients avoided an ALND; 1 patient had a cALND for failure to localize the RRL and 1 patient had a cALND for a false-positive on frozen section. There was no significant difference in clip recovery rates in the pre vs post NAC RRL groups (p=1.00). Conclusion RRL systems are an effective way to guide TAD with a high success rate in identifying and removing previously biopsied nodes. These markers can be placed prior to NAC without migration or deactivation. This strategy allows surgeons to avoid unnecessary cALND. Citation Format: Lilia Lunt, Alison Coogan, Andrea Madrigrano, Cristina O’Donoghue. Targeted Axillary Lymph Node Dissections Using Radar Reflector Localization Can Reduce Unnecessary Axillary Lymph Node Dissections in Node Positive Patients Treated with Neoadjuvant Chemotherapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-14-19.