Evaluation of the metastatic status of lymph nodes identified using axillary reverse mapping in breast cancer patients

Background: Axillary reverse mapping (ARM) is a new technique to preserve upper extremity lymphatic pathways during axillary lymph node dissection (ALND), thereby preventing lymphedema patients with breast cancer. However, the oncologic safety of sparing the nodes identified by ARM (ARM nodes), some of which are positive, has not been verified. We evaluated the metastatic status of ARM nodes and the efficacy of fine needle aspiration cytology (FNAC) in assessing ARM node metastasis. Methods: Sixty patients with breast cancer who underwent ARM during ALND between January 2010 and July 2012 were included in this study. Twenty-five patients were clinically node-positive and underwent ALND without sentinel lymph node biopsy (SLNB). Thirty-five patients were clinically node-negative but sentinel node-positive on the SLND. The lymphatic pathway was visualized using fluorescence imaging with indocyanine green. ARM nodes in ALND field, whose status was diagnosed using FNAC, were removed and processed for histology. We evaluated the correlation between the cytological findings of FNAC and the histological analysis of excised ARM nodes. Results: The mean number of ARM nodes identified per patient was 1.6 +/- 0.9 in both groups. In most patients without (88%) and with (79%) SLNB, the ARM nodes were located between the axillary vein and the second intercostobrachial nerve. FNAC was performed for 45 ARM nodes, 10 of which could not be diagnosed. Six of the patients without SLNB (24%) and onewith SLNB (3%) had positive ARM nodes. Of these sevenpatients, four had >3 positive ARM nodes. There was no discordance between the cytological and histological diagnosis of ARM nodes status. Conclusions: Positive ARM nodes were observed in the patients not only with extensive nodal metastasis but also in those with a few positive nodes. FNAC for ARM nodes was helpful in assessing ARM nodes metastasis, which can be beneficial in sparing nodes essential for lymphatic drainage, thereby potentially reducing the incidence of lymphedema. However, the success of sampling rates needs to be improved.