A large multicenter propensity match study of sentinel lymph node biopsy feasibility in endometrioid variants of endometrial cancer

Introduction: Sentinel lymph node (SLN) biopsy algorithm has been routinely applied in all endometrial endometrioid tumors, however, no studies analyzed the feasibility of SLN mapping in endometrioid variants (EV), which included villoglandular, secretory, ciliated cell, mucinous, and squamous differentiation. This study aimed to demonstrate the feasibility of SLN biopsy in EV of EC. Materials and methods: All patients undergoing minimally invasive surgical treatment for early-stage EC were included in the study. Patients were divided into 2 study groups: Group 1 which included patients with EV, and Group 2 which included patients with typical endometrioid histology. A propensity match analysis was performed according to age (≥65 years vs. no), BMI (≥30 kg/m2 vs. no), and LVSI (present vs. absent). Results: After a 1:5 propensity-matched analysis, a total of 458 patients were identified (Group 1 n = 77, Group 2 n = 381). Overall detection rate was not statistically significant between the EV and the typical endometrioid group (94.8% vs. 92.4%, p = 0.319). Furthermore, neither bilateral nor unilateral detection rate was different between the two groups (70.1% vs. 74.8%, p = 0.267, and 23.4% vs. 17.8%, p = 0.120). BMI ≥30 kg/m2 was the only factor influencing SLN failure (p = 0.013). SLN technique showed excellent sensitivity in both the EV (100% sensitivity, p < 0.001) and the typical endometrioid unit (93.8% sensitivity, p < 0.001). Conclusion: SLN research/detection for EV of endometrial cancer is a feasible and highly sensitive technique. Obesity was confirmed to be a risk factor for SLN failure.