Spatiotemporal epidemiology of hepatocellular carcinoma and its association with environmental factors in Gansu province, 2013–2023

BACKGROUND: Hepatocellular carcinoma (HCC) is a major public health challenge in China, with regional disparities often linked to environmental factors. Gansu Province, characterized by complex topography and climatic heterogeneity, provides a unique setting to examine these determinants. This study characterized the spatiotemporal patterns of HCC incidence in Gansu (2013-2023) and quantified the contributions of terrain, climate, and air quality. METHODS: This population-based ecological study analyzed county-level HCC incidence data (2013-2023) from the Gansu Provincial Cancer Registry. Age-standardized incidence rates (ASIRs) and temporal trends were assessed via direct standardization and Joinpoint regression. Spatial heterogeneity and risk regions (high/low) were identified using a Bayesian hierarchical Besag-York-Mollié (BYM) model. To evaluate environmental drivers, long-term exposures (2003-2013) were correlated with ASIR using Spearman's rank analysis. Multicollinearity was assessed via Variance Inflation Factor (VIF). Finally, the independent attribution of environmental factors was quantified using Ridge Regression with cross-validated penalization, with coefficient stability validated through 1,000 bootstrap resamples. RESULTS: The HCC ASIR in Gansu peaked in 2017 (16.30 per 100,000) before declining to 7.55 by 2023, with a consistent male predominance (sex ratio 2.42:1). Bayesian analysis revealed significant spatial clustering, with high-risk regions concentrated in central and southern counties (e.g., Gannan Plateau). Quantitative attribution demonstrated that topographic features were the dominant drivers, collectively explaining 73.5% of the spatial variance. Altitude emerged as the primary positive driver, contributing 40.3% to the model. Slope exerted a significant negative effect, accounting for 33.2%. In contrast, climatic factors and air pollutants showed minimal and non-significant impacts in the multivariable framework. CONCLUSION: HCC incidence in Gansu Province exhibited substantial temporal fluctuations and marked spatial heterogeneity. Topographic factors-specifically altitude and slope-exerted a predominant influence on the geographic distribution of HCC risk, outweighing meteorological and atmospheric factors at the ecological level. These findings suggest that regional liver cancer surveillance and prevention strategies should prioritize topographic and geographical contexts in environmentally diverse regions.