Comparison of Indocyanine Green as a Standalone Tracer vs Technetium-99m Combined with Blue Dye for Sentinel Lymph Node Detection in Vulvar Cancer

STUDY OBJECTIVE: To compare the sentinel lymph node (SLN) detection rate of indocyanine green (ICG) as a standalone mapping technique with that of technetium-99m combined with blue dye (Tc99m + BD) in early-stage vulvar cancer. DESIGN: Retrospective, single-centre, parallel-cohort study. SETTING: Department of Obstetrics and Gynecology, Semmelweis University, Budapest, Hungary. PATIENTS: Fifty patients with unifocal squamous cell vulvar carcinoma meeting criteria for SLN biopsy (clinical FIGO stage I to II; tumor size <4 cm; stromal invasion >1 mm; clinically and radiologically negative groins). Twenty-four patients underwent SLN mapping with ICG and 26 with Tc99m + BD. INTERVENTIONS: SLN mapping using either ICG with near-infrared fluorescence imaging or Tc99m with BD and gamma-probe guidance, according to institutional practice. MEASUREMENTS AND MAIN RESULTS: Per-patient SLN detection was achieved in all patients in both groups. Per-groin detection was 95.3% (41/43 groins) with ICG and 87.0% (40/46 groins) with Tc99m plus BD, corresponding to an absolute difference of 8.3% (95% CI -0.3% to 21.7%), which did not reach statistical significance (p = .07). The number of SLNs detected per patient did not differ significantly between the ICG and Tc99m + BD groups. CONCLUSION: In this retrospective, single-centre cohort, ICG-based SLN mapping achieved per-patient and per-groin detection rates comparable to those obtained with Tc99m combined with BD. These findings support the technical feasibility of ICG for SLN mapping in vulvar cancer; however, as this study was not designed as a noninferiority trial, no conclusions can be drawn regarding oncologic safety or equivalence between the two techniques.