Flow Chart of the Study Population. a Initial patients identified with surgical management for primary endometrial cancer at Mayo Clinic and Memorial Sloan Kettering Cancer Center (MSKCC), without synchronous invasive cancer or neoadjuvant therapy and, in the MSKCC cohort, without gross intra-abdominal disease or bulky nodes. FIGO indicates International Federation of Gynecology and Obstetrics; LN, lymph node; LND, lymphadenectomy; SLN, sentinel lymph node.