Stage distribution and prognostic accuracy of the 2023 FIGO (the International Federation of Gynecology & Obstetrics) staging system for endometrial cancer: A retrospective cohort study

Objective: To assess the stage distribution and stage-related disease-specific survival rates for endometrial cancer using the FIGO (the International Federation of Gynecology & Obstetrics) 2009 and 2023 staging systems. Further, we sought to evaluate the prognostic utility of additional covariates beyond the FIGO 2023 stage. Methods: Endometrial carcinomas were molecularly classified by the Proactive Molecular Risk Classifier for Endometrial Cancer and staged according to FIGO 2009 and 2023 criteria. Disease-specific survival was calculated as the time from surgery to death from endometrial cancer. Results: Data from 604 patients were analyzed. Median follow-up time was 81 months. A total of 118 stage shifts (19.5%) occurred between the FIGO 2009 and FIGO 2023 systems, with upshifts accounting for 107 (90.7%) of these changes. Within the FIGO 2023 system, molecular classification resulted in restaging of 69 patients (11.4%). Shifts that could alter adjuvant therapy decisions were identified in 23 patients (3.8%). The FIGO 2023 system effectively categorized endometrial cancers into prognostic subgroups. The FIGO 2023 stage, tumor size, positive peritoneal cytology, and mismatch repair deficiency were associated with disease-specific survival in a multivariable analysis, whereas age and adjuvant therapy were not. Conclusion: The FIGO 2023 staging system for endometrial cancer appears highly prognostic. Prognostic assessment of the patients can be further enhanced by readily accessible covariates. A stage shift between the FIGO 2009 and 2023 systems occurs in about one-fifth of patients. The implementation of molecular classification within the FIGO 2023 system bears implications for decisions regarding adjuvant therapy.