Color-segmented fluorescence (“red capping”) sentinel lymph node biopsy in melanoma: a comparative analysis of node positivity rates with indocyanine green

Background Sentinel lymph node biopsy (SLNB) is crucial for staging melanoma and determining metastasis. Indocyanine green (ICG) has emerged as a promising near-infrared fluorescence mapping technique. Recent advancements in near-infrared fluorescence imaging systems, with color-segmented fluorescence (termed “red capping”), may enhance the detection of positive sentinel lymph nodes.Methods This study retrospectively compared node positivity rates between a control group using standard ICG alone and a study group utilizing the newer ICG combined with red capping technology in melanoma patients undergoing SLNB. A total of 70 patients met the study criteria, with 47 in the ICG-alone control group and 23 in the ICG with red capping study group. Both groups achieved a 100% sentinel lymph node detection rate, confirmed by radiotracer.Results The red capping group demonstrated a node positivity rate of 26.1% compared to 19.1% in the ICG-alone group. While this represents a higher proportion of positive nodes, it is important to note that the red capping group also contained a higher percentage of aggressive tumor features, including a 30.4% rate of ulceration (vs 21.3%) and a higher proportion of tumors with >7 mitoses/mm2 (21.7% vs 6.4%). The observed node positivity likely reflects these underlying biological differences between the cohorts rather than the imaging modality itself. Both imaging modes achieved a 100% detection rate when verified by radiotracer, indicating that red capping is an effective and highly visual alternative for intraoperative nodal mapping.Discussion Red capping provides an effective visualization tool for intraoperative lymphatic mapping and demonstrates comparable sentinel node identification to standard ICG fluorescence.