Hybrid 99mTc-ICG Sentinel Lymph Node Mapping in Apparent Early-Stage Epithelial Ovarian Cancer: A First Prospective Evaluation of a True Molecular Hybrid Tracer (HibrOv Trial).

Background/

Objectives

Systematic lymphadenectomy is recommended in apparent early-stage epithelial ovarian cancer (EOC) to assess nodal status, but it is associated with significant morbidity and lacks survival benefit. Sentinel lymph node (SLN) mapping may offer a less invasive alternative, although evidence remains limited due to the complexity of ovarian lymphatic drainage and methodological heterogeneity across studies. This prospective study evaluates the feasibility and diagnostic accuracy of a true hybrid 99mTc-indocyanine green (ICG) tracer for SLN mapping in apparent early-stage EOC.

Methods

A prospective observational study was conducted at a tertiary oncology center between 2021 and 2026. Patients presenting with a suspicious ovarian mass (Group A) or requiring restaging after adnexectomy for confirmed EOC (Group B) underwent SLN mapping using a hybrid 99mTc-ICG tracer injected into the infundibulopelvic (IPL) and/or utero-ovarian ligament (UOL). SLNs were identified using gamma detection and near-infrared fluorescence imaging. All malignant cases underwent complete surgical staging including systematic pelvic and para-aortic lymphadenectomy. SLNs were ultrastaged and compared with the final nodal status.

Results

Forty patients were included; 20 (50%) had malignant tumors. The overall SLN detection rate was 92.5% (37/40), with 100% in malignant cases. Among malignant tumors, 3/20 (15%) had metastatic SLNs, all accurately detected (false-negative rate 0%). Sensitivity and negative predictive value were 100%. Combined pelvic and para-aortic drainage was the most frequent pattern (75%).

Conclusions

SLN mapping may represent a feasible and potentially accurate staging strategy in apparent early-stage EOC. In the present study, a hybrid 99mTc-ICG tracer was associated with high detection rates and complete concordance with final nodal status. These findings support further multicenter validation to define its potential role as an alternative to systematic lymphadenectomy.