The 2023 FIGO staging system in uterine serous carcinoma: Exploring prognostic utility and molecular characterization.

This study evaluated the prognostic performance of the 2023 International Federation of Gynecology and Obstetrics (FIGO) staging system in Chinese uterine serous carcinoma (USC) patients and defined the disease's molecular landscape. Retrospective analysis classified USC patients by both 2009 and 2023 FIGO systems; staging migration was analyzed via cross-tabulation and Sankey diagrams. Molecular classification used the Proactive Molecular Risk Classifier for Endometrial Cancer (ProMisE) algorithm, with human epidermal growth factor receptor 2 (HER2) expression assessed by immunohistochemistry (IHC). Progression-free survival (PFS) and overall survival (OS) were analyzed with Kaplan-Meier curves and log-rank tests; the 2023 system's prognostic ability was validated via time-dependent receiver operating characteristic (ROC) curves, Harrell's C-index, and Akaike's Information Criterion (AIC). The 2023 system induced significant staging migration, mainly from IA/IB to IC (endometrium-confined tumors) or IIC (myometrial invasion). This reclassification achieved better prognostic stratification, shown by higher C-index and lower AIC than the 2009 system. Molecular profiling clarified subtype distribution, and HER2 overexpression was confirmed in substantial subsets, highlighting therapeutic relevance. The 2023 FIGO staging system provides superior prognostic stratification for Chinese USC patients compared to the 2009 version.