RT Journal Article SR Electronic T1 EP626 Lymph vascular space invasion, an independent risk factor of sentinel node mapping failure in endometrial cancer, the sentifail study: a multicentric prospective analysis JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A367 OP A367 DO 10.1136/ijgc-2019-ESGO.683 VO 29 IS Suppl 4 A1 G Sozzi A1 FM Re A1 R Berretta A1 G Lo Balbo A1 V Giallombardo A1 VA Capozzi A1 N Ceresi A1 G Scambia A1 V Chiantera YR 2019 UL http://ijgc.bmj.com/content/29/Suppl_4/A367.1.abstract AB Introduction/Background Sentinel lymph node (SLN) mapping has become the gold standard for surgical staging of early stage endometrial cancer. Side-specific systematic lymphadenectomy is suggested if SLN mapping failed. The objective of this study is to identify clinical and pathological factors associated with failed mapping.Methodology We prospectively evaluated a consecutive series of early stage endometrial cancer patients submitted to SLN mapping with indocyanine green (ICG) near-infrared compatible surgical platforms in two oncological referral centers from January 2018 to January 2019. Indocyanine green was injected intracervical. Bilateral mapping and failed bilateral SLN mapping groups were compared for clinical and pathological features.Results Over the study period, 78 patients met the inclusion criteria. The overall, unilateral, and bilateral SLN detection rates were 88.5%, 15.4%, and 73.1%, respectively. The failed unilateral or no mapping bilateral detection rate was 26.9%. No association between patient demographic characteristics (age, body mass index, histology, grading, tumor size, myometrial invasion and FIGO stage) and SLN mapping failure was observed. Moreover, uterine manipulator or cervical grasping before ICG injection were not associated to failed mapping, while multivariate analysis identified lymph vascular space involvement (LVSI) as the only independent risk factor of SLN mapping failure [OR 4.09 (1.04–1.12), p-value: 0.04].Conclusion Failed SLN mapping is not a rare event andside-specific systematic lymphadenectomy is required to obtain a comprehensive surgical staging. LVSI resulted as the only independent risk factor of SLN mapping failure, probably due to the occlusion of the lymphatic capillaries and consequent failure of the tracer diffusion.Disclosure Nothing to disclose.View this table:Abstract EP626 Table 1 Univariate and multivariate analysis of clinic-pathological parameters as risk factor of failed SLN mappingAbstract EP626 Figure 1 Upper paracervical lymphatic pathway and obturator sentinel node