The involvement of axillary reverse mapping nodes in patients with clinically node-negative breast cancer

Background Axillary reverse mapping (ARM) was developed to preserve the lymphatic drainage from the upper arm during sentinel lymph-node (SLN) biopsy or axillary lymph-node dissection (ALND). However, the oncological safety of ARM has been controversial because of not infrequent involvement of ARM nodes. Methods Patients with clinically negative nodes (cN0) underwent SLN biopsy and ARM. SLNs were identified using blue dye and radioisotope, and ARM nodes were traced using the fluorescent method. Patients with positive SLN underwent the standard ALND. After surgery, they were followed up for more than 3 years. Results A total of 507 patients with cN0 breast cancer were enrolled between May 2009 and November 2017. SLNs were identified in 499 (98%) of 507 patients, and ARM nodes were identified in 159 (31%) patients in the SLN field. The crossover rate of SLN-ARM nodes was 28%. Among 95 patients with positive SLNs, 70 patients underwent conventional ALND. ARM nodes were identified in 65 (93%) of those patients in the ALND field. The mean number of removed ARM nodes was 7.2 (range 0-25) in patients who underwent the standard ALND. Although ARM nodes were involved in 18 of 65 patients, the involved ARM nodes were the same SLNs identified in 14 (78%) patients. Since SLN-ARM nodes should be removed, ARM nodes were involved only in 4 (5.7%) patients after SLN biopsy. Conclusions Except for positive SLN-ARM nodes, the involvement of ARM nodes is infrequent in patients with positive SLN.