From Blue Dye to Multimodal-Guided Surgery: The Evolution of Sentinel Lymph Node Mapping in Vulvar Cancer - A Narrative Review.

The surgical management of inguinofemoral lymph nodes in early-stage vulvar cancer has progressively shifted from complete lymphadenectomy toward selective sentinel lymph node (SLN) biopsy, reducing treatment-related morbidity while preserving oncologic safety. This narrative review summarizes the historical, technical, and clinical evolution of SLN mapping, from vital blue dyes to radiotracer-based validation and contemporary multimodal image-guided approaches. A literature search of PubMed/MEDLINE and Scopus was performed through May 2026, including landmark prospective studies, multicenter validation trials, systematic reviews, meta-analyses, guidelines, and studies evaluating indocyanine green (ICG) and hybrid radioactive-fluorescent tracers. Early blue dye studies established the feasibility of lymphatic mapping, whereas technetium-99m, lymphoscintigraphy, and gamma-probe guidance provided the reproducibility required for prospective validation. GROINSS-V I supported safe omission of complete inguinofemoral lymphadenectomy in carefully selected SLN-negative patients, complemented by diagnostic validation in GOG-173; subsequent evidence linked SLN tumor burden to prognosis and enabled risk-adapted management of positive nodes. ICG-based near-infrared fluorescence has emerged as a valuable tool for real-time visualization and may improve intraoperative guidance. However, most comparative studies have evaluated fluorescence after radiotracer-based localization or defined the SLN according to technetium uptake, limiting conclusions regarding stand-alone interchangeability. Current evidence therefore supports ICG primarily as an adjunct within multimodal mapping rather than as a validated replacement for technetium-99m. Future progress should focus on standardized fluorescence protocols, rigorously sequenced ICG-first validation, hybrid radioactive-fluorescent strategies, and integration of imaging-derived and artificial intelligence-based tools into individualized groin management.