Clinical application value of the updated FIGO 2023 classification compared with FIGO 2009 for endometrial cancer staging in a Chinese cohort.

Abstract

Objective: To compare the predictive performance of the International Federation of Gynecology and Obstetrics (FIGO) 2009 and FIGO 2023 staging systems for endometrial cancer (EC) and to assess whether FIGO 2023 system better predicts patient prognosis.

Methods: A retrospective analysis of 640 EC patients was conducted, with staging according to the 2009 and 2023 FIGO systems. Kaplan-Meier survival analysis, hazard ratios (HRs), Harrell's concordance index (C-index), and Akaike's Information Criterion (AIC) were used to assess model performance.

Results: A change to a higher substage occurred in 148 patients (23.1%), whereas 12 patients (1.9%) were down-staged, based on the FIGO 2009 staging system. Among early-stage patients, 9 and 62 were reclassified from early-stage (I and II) to IAm_POLEmut and IICm_p53abn, respectively, according to the molecular subtypes POLEmut and p53abn, and showed distinctly different prognoses (5-year overall survival [OS]: 100% vs. 75.3%). The 5-year OS and disease-free survival (DFS) rates were better for stage IA3 than for stage IIIA1 (OS: 91.7% vs. 71.6%, DFS: 91.7% vs. 71.3%). Among patients with advanced EC, those with the p53abn molecular subtype had the worst prognoses (5-year OS: 41.6%). Compared to FIGO 2009, FIGO 2023 showed significantly higher HRs for OS and DFS (p<0.001), higher C-index values (0.751 vs. 0.711, 0.750 vs. 0.709), and lower AIC values (1,316.919 vs. 1,338.928, 1,315.444 vs. 1,337.864).

Conclusion: The FIGO 2023 system provided a better model fit and higher predictive accuracy than the FIGO 2009 system. Molecular subtyping was crucial for prognoses of patients with advanced EC (stage III/IV).