Introduction/Background Sentinel lymph node biopsy (SNB) for early endometrial cancer is becoming method of choice. Despite prospective data availability there is lack of harmonization in terms of tracers and routes for application.

Methodology Prospective multicentric observational CEEGOG study (NCTO4665544) analyzed SNB using two concurrent tracers administered intracervically in different ways (ICG and radioactive tracer-Tc) within the same patient. The protocol demanded first to detect the SLN using gamma probe (before turning on infrared light), followed by ICG detection. Pelvic±paraaortic lymphadenectomy (LND) followed. The unilateral detection rate (per hemipelvis), the bilateral detection rate (per patient), sensitivity to reflect status of nodes and consistency in SLN detection were calculated.

Results 86 patients (172 hemipelvices) from 6 centers were included. Endometrioid type (77.9%), G2/3 (70.9%) and no LVI (86%) were predominant. The unilateral detection rate was 69.1% for Tc, 84.9% for ICG and 88.4% for both tracers. The bilateral detection rate was 57.0% for Tc, 77.9% for ICG and 82.6% for both. The sensitivity of SLN method to reflect status of nodes was 98.3% for Tc alone, 98.5% for ICG alone and 98.6% for both. In 5 hemipelvices (3%) the Tc detected SLN was different and in different region than ICG detected SLN. All SLN and nodes after LND were in those cases negative. It happened in two different centers that included about 25% of patients each.

Conclusion The result of prospective real-life resembling study showed the superiority of ICG and combination of tracers to Tc alone in unilateral and bilateral detection rate. When SLN was detected, the sensitivity to reflect status of nodes was similar between the tracers and their combination. The discrepancy between SLN traced by one or another tracer within the same patient in 3% of hemipelvices needs clarification of clinical relevance in times of precision medicine development.

Disclosures No disclosures.