Abstract P1-01-02: Pathologic nodal status is a predictor for metastatic disease in lymph nodes identified by axillary reverse mapping

Abstract

Abstract Background Breast cancer is the most common cancer in female patients worldwide. Although axillary management in breast cancer has been de-escalated to reduce untoward effects, breast cancer-related lymphedema (BCRL) is still not uncommon. Axillary reverse mapping (ARM) emerges as a novel technique that identifies the lymphatic system draining the upper extremities. Preservation of this system and associated lymph nodes theoretically reduces the chance of BCRL. However, concerns regarding oncologic safety have limited the adoption of the technique. Objective To identify factors associated with metastatic disease in lymph nodes identified by ARM in breast cancer patients. Materials and methods Breast cancer patients treated at King Chulalongkorn Memorial Hospital from October 2018 to January 2021 who underwent axillary lymph node dissection (ALND) underwent concurrent ARM whereby five milliliters of 1% isosulfan blue dye was injected at the medial aspect of the arm as previously described elsewhere. Patient demographics and clinical data such as clinical staging, pathological staging, cancer subtype, and whether neoadjuvant chemotherapy was administered were collected and analyzed. Result Thirty-six patients with a median age of 57 were included in this prospective study. ARM lymph node identification success rate was 83% (30 of 36 patients) with a median of 2 identified ARM lymph nodes (range 0-11 nodes). Metastatic disease in ARM nodes was present in 30% of patients. ARM success rate did not depend on whether preoperative chemotherapy had been given (ARM lymph nodes identified in 7 out of 8 patients without preoperative chemotherapy and 23 out of 28 in patients with preoperative chemotherapy; p=0.36). There was no statistically significant difference in metastatic disease in ARM-identified nodes and clinical stage (stage II=13.3%, stage III=33.3%, and stage IV=50.0%; p=0.18). However, higher pathologic N stage was associated with finding metastasis in ARM-identified lymph nodes (N0=0%, N1=15.8%, N2=33.3%, and N3=80%; p=0.005). Conclusions ARM is a novel technique which can potentially reduce BCRL. However, a significant number of ARM lymph nodes were found to have pathologically-proven metastatic disease, especially in higher pathologic N stages (pN2 and pN3). Therefore, for oncologic safety, consideration should be given to removal of all ARM lymph nodes in breast cancer patients undergoing formal axillary dissection. Keywords: Axillary Reverse Mapping, Axillar dissection, Lymphedema, Breast Cancer Citation Format: Rak Saengphongchawan, Sopark Manasnayakorn. Pathologic nodal status is a predictor for metastatic disease in lymph nodes identified by axillary reverse mapping [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-01-02.