Feasibility of Axillary Reverse Mapping and Clinicopathological Features Predicting ARM Node Metastasis in Breast Cancer-a Pilot Study.

The axillary reverse mapping (ARM) technique has been described as an attempt to map and preserve the upper extremity lymphatic drainage during axillary lymph node dissection (ALND) and/or SLNB. This technique is based on the hypothesis that the lymphatic pathway from the upper extremity is not involved by metastasis from primary breast cancer. The ARM node/s however, has been found, in various studies, to be involved with metastatic foci in patients with extensive axillary lymph node metastases. Therefore, the oncological safety of this procedure has not yet been determined. In this pilot study, we assessed the ARM node intraoperatively for various parameters and compared it to final HPR, to try and determine the oncologic safety of preserving the ARM node. Seventy-two breast cancer patients were screened for this prospective pilot study which was planned to recruit 20 patients. The study was initiated on May 2014, 20 patients were recruited till July 2015. Eligibility criterion was as follows: patients requiring primary axillary lymph node dissection based on a clinically positive axilla. Forty-five patients were ineligible because they had either received neoadjuvant chemotherapy or underwent previous axillary surgery or axillary radiation (exclusion criteria). Seven patients refused to give consent. ARM node identification rate was 75%. The most common location of the ARM node was lateral to the latissimus dorsi pedicle (42.10%), none of them being malignant. None of the oval or firm nodes were malignant. Tumor deposits were identified in 13%. Fine-needle aspiration cytology (FNAC) had 100% specificity, 94.4% negative predictive value, 100% positive predictive value, and 50% sensitivity. ARM is feasible using blue dye alone, with an acceptable identification rate. Location, consistency, and intraoperative FNAC of the ARM node, put together, may be reliable parameters to predict involvement of the ARM node with metastasis.