Background: Lip and oral cavity cancers represent a significant public health burden in Southeast Asia, with Thailand reporting an age-standardized disability-adjusted life year rate of 79.7 per 100,000 population. Following implementation of Thailand's national oral cancer screening program as a universal health coverage benefit package in 2022, characterizing provincial-level spatial patterns has become essential for equitable resource allocation and effective program optimization. Geographic variation in cancer burden often reflects underlying differences in risk factor distribution and healthcare infrastructure, making spatial analysis critical for evidence-based intervention targeting.
Objectives: To characterize the spatial distribution of oral cancer incidence across Thailand's 77 provinces using national cancer registry data and identify high-risk geographic clusters to inform targeted screening interventions and equitable public health resource allocation.
Methods: This descriptive study analyzed standardized incidence ratios (SIRs) of lip and oral cavity cancer (ICD-10: C00-C06) using 2024 data from Thailand's national cancer registry. Age-standardized incidence rates and SIRs were calculated for each province. Spatial autocorrelation was assessed using Global Moran's I and Local Indicators of Spatial Association (LISA). Hot spot analysis employed Getis-Ord Gi* statistics to identify statistically significant geographic clusters. Bayesian estimation with posterior exceedance probabilities (SIR > 1) was used to quantify high-risk cluster identification.
Results: Of 3,176 incident oral cancer cases identified across 77 provinces, the age-standardized incidence rate was 3.0 per 100,000, with a male-to-female ratio of 1.69:1 and median age of 62 years (IQR: 54–72). Tongue was the predominant cancer subsite. Spatial analysis revealed significant clustering (Global Moran's I = 0.45, p < 0.001), indicating strong positive spatial autocorrelation. Getis-Ord Gi* analysis identified statistically significant hot spots in Central, lower-Northeastern, and upper-Southern regions. Bayesian analysis with high posterior exceedance probability (> 1) confirmed high-risk clusters predominantly in these same geographic areas, demonstrating consistency across analytical approaches.
Conclusions/Implications: This analysis demonstrates substantial geographic heterogeneity in oral cancer incidence across Thailand, with distinct high-risk clusters requiring prioritized screening and prevention resources. The identification of spatial clusters provides actionable evidence enabling the Ministry of Public Health to optimize resource allocation within Thailand's Universal Health Coverage framework, particularly for the Health Promotion & Disease Prevention service component. This spatially informed surveillance approach directly supports national oral cancer control policy refinement and contributes to Thailand's implementation of the WHO Global Strategy and Action Plan on Oral Health 2023–2030.

Spatial Epidemiology of Oral Cancer in Thailand: Multiple Analytical Approaches Demonstrating Geographic Heterogeneity and High-Risk Clusters: (a) Standardized Incidence Ratios (SIR) by province (b) Bayesian posterior exceedance probabilities (c) Local Mo