Territorial inequalities in cancer mortality in Chile, 2002-2022: a rurality-continuum analysis using spatiotemporal Bayesian models.

OBJECTIVE

To examine how cancer mortality in Chile varied across a continuous rurality gradient and to identify territorial differences in mortality risk and temporal trends.

METHODS

We analyzed cancer deaths in 343 continental municipalities between 2002 and 2022. A continuous Index of Relative Rurality was constructed using indicators of population concentration and spatial accessibility. Municipal mortality was modeled using Bayesian spatiotemporal models adjusted for age and sex. Exploratory analyses of the rurality gradient identified a threshold with a change in mortality-risk patterns, which was used to compare trajectories.

RESULTS

A clear inflection in the mortality-rurality relationship emerged around an index value of 0.30, separating two territorial mortality profiles. Mortality declined nationally but reductions were slower in more rural municipalities. Cancers historically linked to structural disadvantage-such as stomach, gallbladder, and cervical cancer-showed higher mortality risks in more rural areas. In contrast, breast, lung, and colorectal cancers showed higher risks in less rural municipalities. Several cancers, including colorectal, lung, kidney, and bladder, also displayed less favorable temporal trends in more rural territories.

CONCLUSIONS

Distinct trajectories along the rural-urban continuum reveal territorial inequalities that may remain hidden in national averages. These findings support targeting prevention efforts to higher-risk territories.