Is Sentinel Lymph Node Sampling Indicated in Endometrial Intraepithelial Neoplasia? [37F

Abstract

INTRODUCTION: We sought to identify uterine risk factors and frequency for which lymph node sampling was indicated among women undergoing hysterectomy for a preoperative diagnosis of endometrial intraepithelial neoplasia (EIN). METHODS: We performed a retrospective cohort study of patients undergoing hysterectomy with a preoperative diagnosis of EIN from 2016-2017. When cancer was found, the Mayo criteria (grade 1 or 2 tumor, depth of invasion <50%, and tumor size >2 cm) were used to determine if lymphadenectomy would have been indicated. Descriptive statistics were used. Approval was obtained from the institutional IRB. RESULTS: Fifty-three subjects were included; mean age was 60.1 years (SD: 22.9). Hysterectomy pathology was benign in 28% (n=15), EIN in 47% (n=25), and endometrioid adenocarcinoma (EC) in 25% (n=13). All cancers were FIGO Stage IA, grade 1 (n=9) or 2 (n=4). No cases had LVSI; mean depth of invasion was 3.5% (0-22%, SD 7.1%). Four cases had tumors ≥-2 cm; one of those was confined to a large polyp. Ultimately, 7.5% (n=4/53) of EIN patients met Mayo criteria; all of these were due to tumor size >2 cm. Using historical models, the risk of lymph node positivity is <5% for each of the 4 patients who met Mayo criteria. Therefore, an overall cohort of >250 patients with EIN would require sampling to identify one patient with metastatic EC. CONCLUSION: In an era of pre-hysterectomy sentinel nodal sampling, these findings provide new data with which to counsel patients on the potential benefits and limited yield of SLN biopsy when undergoing surgery for EIN.