2023 FIGO Staging of Endometrial Cancer with Molecular Classification: Dawn and Challenges

Objective: To assess the prognostic performance of the 2023 FIGO staging system for endometrial cancer, which incorporates molecular classification (FIGO 2023m), we analyzed survival outcomes and compared them with the 2009 FIGO system (FIGO 2009). Methods: We retrospectively reviewed 720 patients with endometrial cancer treated between 2013 and 2021. Staging was performed according to FIGO 2009 and FIGO 2023m. Progression-free survival (PFS) and overall survival (OS) were estimated using Kaplan-Meier analysis. Factors associated with survival were identified through univariate and multivariate Cox proportional hazards analyses. Results: Of the 720 patients, 27.4% (197/720) were reclassified under FIGO 2023m, and 182 were upstaged from stage I to stage II, primarily due to p53 abnormalities (54.9%). Patients with stage I disease according to FIGO 2023m had comparable survival rates (PFS: 95.3% vs. 92.8%; OS: 99.2% vs. 95.9% under FIGO 2009). Within stage II, OS in patients classified as FIGO 2023m IIC was slightly lower than in stage IIC but did not differ statistically (92.3% vs. 86.9%). Aggressive histology, positive peritoneal cytology, and deep myometrial invasion were associated with poorer outcomes. Patients harboring POLE mutations showed excellent prognosis (5-year OS, 100.0%), even at advanced stages. Conclusion: Compared with FIGO 2009, the FIGO 2023m staging system offers improved prognostic value and better discriminative ability. Incorporating molecular subtyping is crucial even in advanced disease. However, omitting peritoneal cytology from prognostic assessment may risk undertreatment. Continued refinement in quantifying lympho-vascular space invasion (LVSI) and differentiating complex endometrial-myometrial junctions from genuine myometrial invasion remains a challenge.