Axillary Reverse Mapping: Mapping and Preserving Arm Lymphatics May Be Important in Preventing Lymphedema During Sentinel Lymph Node Biopsy

Background: Several recent reports have shown a lymphedema rate of about 7% with sentinel lymph node biopsy (SLNB) only. We hypothesized that this higher than expected rate of lymphedema may be secondary to disruption of arm lymphatics during an SLNB procedure. Study Design: This IRB-approved study, from May 2006 to June 2007, involved patients undergoing SLNB with or without axillary lymph node dissection. After sentinel lymph node (SLN) localization with subareolar technetium was assured, 2 to 5 mL of dermal blue dye was injected in the upper inner arm for localization of lymphatics draining the arm (axillary reverse mapping, ARM). The SLNB was then performed through an incision in the axilla. Data were collected on identification rates of hot versus blue nodes, variations in ARM lymphatic drainage that might impact SLNB, crossover between the hot and the blue lymphatics, and final pathologic nodal diagnosis. Results: Median age was 57.6 ± 12.5 years. Lymphatics draining the arm were near or in the SLN field in 42.7% (56 of 131) of the patients, placing the patient at risk for disruption if not identified and preserved during an SLNB or axillary lymph node dissection. ARM demonstrated that arm lymphatics do not cross over with the SLN drainage of the breast 96.1% of the time and that none of the ARM lymph nodes removed were positive, even when the SLN was (5 of 12). Seven (5.5%) blue ARM lymphatics were juxtaposed to the hot SLNBs. Conclusions: Disruption of the blue ARM node because of proximity to the hot SLN may explain the surprisingly high rate of lymphedema seen after SLNB. Identifying and preserving the ARM blue nodes may translate into a lower incidence of lymphedema with SLNB and axillary lymph node dissection.