Outcomes of Low-Risk Endometrial Cancer With Isolated Tumor Cells in the Sentinel Lymph Nodes: A Prospective, Multicenter, Single-Arm Observational Study

Inclusion Criteria: * Low-risk endometrial cancer, defined as endometrioid, grade 1 or 2, International Federation of Gynecology and Obstetrics (FIGO) 2009 stage IA (FIGO 2023 stages IA1 and IA2), without substantial/extensive LVSI (≥ 5 vessels involved) at final pathology. Patients with focal LVSI (\< 5 vessels involved) will be included. * Complete surgical staging, including pelvic sentinel lymph node (SLN) biopsy per National Comprehensive Cancer Network (NCCN) guidelines and ultrastaging. * Extent of disease in SLN: ITC (defined as tumor cell aggregates ≤ 0.2 mm or \< 200 cells) * No adjuvant treatment after surgery * Research consent provided. Exclusion Criteria: * Prior neoadjuvant chemotherapy. * Planning to receive adjuvant treatment. * Presence of synchronous cancer (excluding non-melanoma skin cancer). * Extent of disease in SLN: micrometastasis (\> 0.2 to ≤ 2.0 mm) or macrometastasis (\> 2.0 mm). * Presence of substantial/extensive LVSI (≥ 5 vessels involved) at final pathology. * Prior invasive cancer diagnosis within 5 years of study entry (excluding non-melanoma skin cancer).