Persistent geographic inequalities in oesophageal cancer mortality in Spain despite overall declines

Oesophageal cancer remains a leading cause of cancer mortality worldwide, with marked geographical variation. This study examined sex-specific temporal trends and subnational spatial patterns in oesophageal cancer mortality across Spain from 1999 to 2023.

We conducted an ecological study using province-level mortality data from the Spanish National Institute of Statistics. Sex-stratified Bayesian hierarchical spatiotemporal models were fitted using Integrated Nested Laplace Approximation (INLA) to estimate smoothed relative risks (RRs), accounting for spatial, temporal, and interaction effects. High-risk areas were identified using posterior probabilities (PP > 0.95).

Between 1999 and 2023, male mortality declined significantly; the smoothed RR fell from 1.22 (95 % Credible Interval [CrI]: 1.171.26) to 0.81 (95 % CrI: 0.770.86). Female mortality remained characteristically low and stable. Spatial heterogeneity explained 60 % of total variance in men and a remarkable 92 % in women, far outweighing temporal trends. Persistent high-risk clusters traversed the northern Atlantic/Cantabrian axis and the Canary Islands, while central provinces consistently showed reduced risk. Spatiotemporal interactions revealed diverging local trajectories, including sustained excess risk in the Canary Islands despite national improvements.

Spain has achieved substantial reductions in oesophageal cancer mortality, particularly among men; however, pronounced and persistent regional disparities remain. As an ecological study, these findings reflect geographically patterned exposures rather than individual-level causality. The results emphasise the need for geographically targeted prevention, strengthened surveillance, and equitable access to specialised diagnostic and surgical services to reduce inequalities and improve outcomes nationwide.