Laparoscopic sentinel node mapping with intracervical indocyanine green injection for endometrial cancer: The SENTIFAIL study- A multicentric analysis of predictors of failed mapping

Objectives Laparoscopy is commonly used for endometrial cancer treatment, and sentinel lymph node (SLN) mapping has become the standard procedure for nodal assessment. Despite the standardization of the technique, there is no definitive data regarding its failure rate. The objective of this study is to identify factors associated with unsuccessful SLN mapping in endometrial cancer patients undergoing laparoscopic SLN mapping after intracervical indocyanine green (ICG) injection. Methods We retrospectively evaluated a consecutive series of endometrial cancer patients who underwent laparoscopic SLN mapping with intracervical ICG injection, in four oncological referral centers from January 2016 to July 2019. Inclusion criteria were biopsy-proven endometrial cancer, total laparoscopic approach, and intracervical ICG injection. Exclusion criteria were evidence of lymph node involvement or extrauterine disease at pre-operative imaging, synchronous invasive cancer, the use of tracers different from ICG, and the use of neoadjuvant treatment. Bilateral and failed bilateral SLN mapping groups were compared for clinical and pathological features. In patients with an unsuccessful procedure, side-specific lymphadenectomy was performed. Logistic regression was used to identify predictors of failure. Results A total of 376 patients were included in the study. The overall bilateral and unilateral SLN detection rates were 96.3%, 76.3%, and 20.0% respectively. The failed bilateral mapping detection rate was 23.7%. The median number of sentinel nodes removed was 2.2 (range, 0-5). After multivariate analysis, lymph vascular space involvement [OR 2.4 (1.04-1.12), P=0.003], non-endometrioid histology [OR 3.0 (1.43-6.29), P=0.004], and intraoperative finding of enlarged lymph node [OR 2.3 (1.01-5.31), P=0.045] were identified as independent predictors of failure of SLN mapping. Conclusion Lymph vascular space involvement, non-endometrioid histology, and intra-operative finding of enlarged lymph nodes were identified as independent risk factors for unsuccessful mapping in patients undergoing laparoscopic SLN mapping.