Endometrial cancer is a malignant epithelial tumor of the uterine corpus that is the fourth most common female malignancy in the United States [1,2]. Nearly 68,000 new diagnoses are estimated in 2024 and the population-level incidence and mortality rates of endometrial cancer have gradually increased over time [1,3,4].

The prognosis of patients diagnosed with endometrial cancer is largely dependent on the stage of cancer [5]. In addition to prognostication, staging data is used to guide anti-cancer therapy [[6], [7], [8]]. Historically, the staging schema for endometrial cancer has relied on the prognostic factors including local, nodal, and distant tumor data [9]. In 2023, the International Federation of Gynecology and Obstetrics (FIGO) Women's Cancer Committee revised the endometrial cancer staging schema (Table 1 and S1) [10]. This is the first revision in the past 15 years from prior revision which occurred in 2009 [11].

There are a number of important changes for the FIGO 2023 staging schema [10,12]. First, the staging criteria incorporate histologic subtype in two-tier fashion (non-aggressive or aggressive) in early-stage disease given its prognostic significance [13]. Second, lympho-vascular space invasion (LVSI), which is an important prognostic feature in endometrial cancer [14,15], is now utilized to assign stage. Third, there is greater sub-division of some stages based on anatomical site of disease which increased from 9 to 19 sub-stages (Table 1 and S1). Lastly, the staging schema now includes molecular abnormalities reflecting the survival clustering ability in high-throughput analysis via four biomarker status (POLEmut, MMRd, NSMP, and p53abn) [10,16].

The evaluations of the revised 2023 FIGO staging schema for endometrial cancer have only recently begun and the performance characteristics have not been completely evaluated to date [[17], [18], [19], [20], [21], [22]]. There are conflicting views and debates on this newly introduced staging schema across investigators, and some reported the enhanced and more granular prognostic performance compared to prior staging schema [17,20,21,[23], [24], [25]] while other voiced and raised counterpoints for the sudden major changes, incorporation of non-anatomical factors, and lack of treatment ramification [[26], [27], [28]]. The objective of the current study was to assess the prognostic ability of the 2023 FIGO staging schema for endometrial cancer.