Global trends and disparities in uterine corpus cancer by histological subtype: a population-based analysis

Background: Uterine corpus cancer (UCC) demonstrates significant global heterogeneity in incidence patterns, with aggressive histological subtypes contributing disproportionately to mortality despite their lower prevalence. Current understanding of temporal trends and geographical variations in subtype distribution remains fragmented, particularly in low- and middle-income countries (LMICs). Methods: This population-based study analyzed Cancer Incidence in Five Continents (CI5) data (Volumes I-XII, 1988-2017) from 65 countries across all development levels. Age-standardized incidence rates (ASRs) were calculated by histological subtype (endometrioid, serous, clear cell, carcinosarcoma, other specified, unspecified) and evaluated using joinpoint regression for temporal trends and geospatial mapping for regional patterns. Subtype distributions were analyzed by Socio-demographic Index (SDI) level and age group. Results: Three key findings emerged: 1) Distinct geographical patterns with Eastern Europe showing peak historical rates (Czech Republic ASR 31.16) now declining (−34%), while Asia demonstrates rapid increases (Japan + 37%, South Korea + 188%); 2) Strong socioeconomic gradients with adenocarcinoma comprising 84% of cases in high-SDI countries versus predominance of unspecified types (≤30%) in low-SDI regions; 3) Characteristic age distributions peaking at 65-69 years (ASR 54.54) with elderly populations showing disproportionately high unspecified cases (28-35%). Temporal analysis revealed accelerating trends in aggressive subtypes (serous carcinoma + 1.8%/year in North America) contrasting with stable endometrioid rates in most regions. Conclusion: This study highlights the evolving global epidemiology of UCC by histological subtype, emphasizing how development level influences disease patterns and diagnostic capacity. The findings underscore the urgent need for subtype-specific prevention strategies and improved pathological infrastructure to address global disparities in uterine cancer burden.