Abstract P2-14-11: Oncological outcomes in patients undergoing targeted axillary dissection with carbon marker
Authors: Budel Lucas R. , Spautz Cleverton C. , Louveira Maria Helena , Cavalcanti Teresa Cristina S. , Fornazari Alessandra C. , Gasperin Plinio , Nissen Leonardo P. , Budel Vinicius M. 
Published: March 2023

Abstract
Background: The use of axillary marking before neoadjuvant systemic therapy (NST) is the standard of care in patients with positive lymph nodes (LN). Several methods have been tested leading to reduced false negative rate compared to sentinel lymph node biopsy (SLNB). With the increase in therapies in patients with residual disease, it is necessary to improve the accuracy of the axillary assessment. The aim of this study was to evaluate oncological outcomes in patients undergoing targeted axillary dissection with positive LN pre-NST marked with 4% carbon marker, the secondary objective was to evaluate the association between SLNB and pre-NST marked lymph node. Methods: A prospective study was performed in patients with cT1-T4, cN1-N2 breast cancer who underwent NST. An ultrasound-guided 4% carbon marking was performed before proposed treatment. After NST, the carbon marked lymph node (CMLN) was identified and resected associated with SLNB. When at least one lymph node was positive, axillary dissection was performed. The oncological outcomes registered were overall survival (OS), specific survival (SS), disease-free survival (DFS), axillary recurrence (AR) and local recurrence (LR). Results: 176 patients operated between July 2014 and January 2019 were included in the analysis. The CMLN were identified in 168/176 (95.4%) and the SLNB 145/176 (82.3%) operations. SLNB and CMLN were coincident in 93/176 (52.8%) cases. The LNs were not coincident in 44/176 (25%) cases and at least one of the methods were not identified in 39/176 (22.1%). When condensing the lymph nodes not found as positive lymph node, the sample agreement was 148/176 (81.4%) [Kappa = 0.67 (95%CI: 0.56 – 0.78)], when separating the positive lymph nodes from the lymph nodes not found, the agreement was 133/176 (75.6%) [Kappa = 0.56 (95%CI: 0.46 – 0.66)] (Table 1). With a mean follow-up of 49 months, 168 patients were included in the analysis of oncologic outcomes. Among the patients analyzed, 7/168 (4,1%) had LR, 5/168 (2,9%) had AR, 28/168 (16.6%) had distant recurrences [DFS = 83.3%]. There were 10/168 (5,9%) deaths [OS = 94%], with 5 confirmed by breast cancer and 4 of undetermined cause. There was a significant association between axillary dissection and axillary recurrence (0 versus 6% p = 0.012). OS for clinical stages 2B, 3A and 3B were 97, 88 and 87.5% respectively. Conclusions: The use of 4% carbon marker is a feasible and cheap method for targeted axillary dissection. The oncological outcomes are compatible with the survival curves of the American Joint Committee on Cancer 8th edition, therefore, a safe tool to spare women cN+ from axillary dissection when there is a complete axillary response to NST. The concordance rate between the CMLN and the SLNB was moderate when we took into account the failure of some method, noting the need for a supplementary method to the SLNB after NST.
Frequency and percentages of anatomopathological results and methods of lymph node identification. SLNB = sentinel lymph node biopsy; CMLN = carbon marked lymph node
Occurrence of oncological outcomes
Citation Format: Lucas R. Budel, Cleverton C. Spautz, Maria Helena Louveira, Teresa Cristina S. Cavalcanti, Alessandra C. Fornazari, Plinio Gasperin, Leonardo P. Nissen, Vinicius M. Budel. Oncological outcomes in patients undergoing targeted axillary dissection with carbon marker [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 P2-14-11.