Geographic inequalities and gender-specific trends in oropharyngeal cancer mortality in Spain

BACKGROUND: Consistent geographical disparities in oropharyngeal cancer (OPC) mortality rates have been observed across Europe, with distinct trends emerging among men and women. This study provides a detailed subnational analysis of OPC mortality in Spain between 1999 and 2023, categorised by gender and administrative region. MATERIAL AND METHODS: We conducted an ecological analysis using ICD-10 C10 mortality data for all 50 Spanish provinces and the two autonomous cities (Ceuta and Melilla). Hierarchical Bayesian spatio-temporal Poisson models, fitted via INLA, were employed to decompose variance and identify gender-specific risk patterns. RESULTS: Gender-specific patterns were markedly distinct. Male mortality showed a strong spatial structure (88.1% of variance), with persistent high-risk clusters in Northern Spain (Asturias, A Coruña, Cantabria) and the Canary Islands. Despite a modest national decline, risk often remained stable or increased in these high-risk areas; for instance, Cantabria's relative risk (RR) peaked at 2.62 in 2023. This pattern is consistent with entrenched traditional risk factors (tobacco and alcohol use). Conversely, female mortality was dominated by a strong national temporal increase (17.2% of variance), likely reflecting a growing HPV-associated burden. Risk escalated nearly uniformly across the country, rising from RR 0.62 in 1999 to 1.54 in 2023. Localised temporal deviations were significant for men (10.2% interaction), but negligible for women (0.4%), confirming a synchronised, nationwide female trend. CONCLUSIONS: OPC mortality dynamics demand dual intervention strategies. Deep-rooted gender disparities in the northern and island provinces suggest strengthening tobacco and alcohol control campaigns. The rapid and widespread increase in female mortality highlights the need of expanding HPV vaccination programmes nationwide.