A Prospective Multi-Institutional Trial Examining the Feasibility, Accuracy and Learning Curve of Fluorescence Imaging for Sentinel Node Localization in Melanoma

Introduction: Sentinel node biopsy (SNB) is a standard component of staging for patients with localized melanoma. We performed a prospective trial to assess safety and feasibility of using fluorescence imaging for localizing sentinel nodes. Methods: Patients with melanoma of the upper or lower extremity who met criteria for SNB were prospectively enrolled. Surgeons were blinded to lymphoscintigraphy results and performed SNB using indocyanine green (ICG) and fluorescence imaging alone followed by confirmation with gamma probe. Safety of ICG, operative metrics and success of localization were recorded. Results: Four experienced melanoma surgeons identified 55 sentinel nodes in 35 evaluable subjects. Each surgeon enrolled at least 8 subjects. The success with ICG alone for the first SN was 83%, second SN 60% and third SN 0%. Success was higher in the groin than axilla for the first SN (93 vs 76%) but lower for the second SN (0 vs 90%). Body mass index did not impact success rate. Time to identification of first SN was similar among surgeons and over time. There were no adverse events related to ICG. Conclusion: Fluorescence imaging is a reliable method to identify sentinel nodes, but cannot replace lymphoscintigraphy. The learning curve for this technique is more than 8 subjects and each surgeon has incorporated this technique differently into their practice. ICG could replace blue dye given the benefits of real-time lymphangiography and its low side effect profile and cost compared with isosulfan blue. Drawbacks include limited visibility through tissue and in multiple draining nodal basins.