Scientific Impact Award: Axillary reverse mapping (ARM) to identify and protect lymphatics draining the arm during axillary lymphadenectomy

Introduction: The axillary reverse mapping (ARM) procedure distinguishes lymphatics draining the arm from those draining the breast. The aim of this study was to assess the ability of ARM to identify and preserve lymphatics draining the arm and the impact on lymphedema. Methods: This study included 220 patients undergoing sentinel lymph node (SLN) biopsy (SLNB) with or without axillary lymph node dissection (ALND) from May 2006 to September 2008. After SLN localization with a radioactive tracer, blue dye was used to map ARM lymphatics. Data were collected on identification and variations in lymphatic drainage, crossover rate, the incidence of metastases, and nodal status. Results: Crossover (ARM = SLN) occurred in 6 patients (2.8%). ARM lymphatics were near or in the SLN field in 40.6% of patients, placing it at risk for disruption during lymphadenectomy. ARM lymphatics juxtaposed to the hot SLNB (n = 12 [5.6%]) were preserved. Fifteen ARM nodes were excised and were negative even in positive axillae. There were no cases of lymphedema at 6-month follow-up where ARM nodes were preserved. Conclusion: Confluence of the arm and breast drainage is rarely the SLN, and none of these nodes contained metastases. Preserving the ARM nodes may translate into a lower incidence of postoperative lymphedema.