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).