Breast cancer mortality in Argentina, 1991-2023: a nationwide ecological study of spatiotemporal patterns and regional inequalities.

Abstract

Breast cancer mortality is geographically heterogeneous in Argentina, but long-term spatiotemporal evidence by age group is limited. We described temporal trends and spatial clustering of breast cancer mortality in Argentina from 1991 to 2023 by region and age. We conducted a longitudinal ecological study using death certificates with breast cancer as the underlying cause. Crude rates and age-standardised mortality rates (ASMR) per 100,000 women were estimated overall and truncated for <45 and ≥45 years using the WHO 2000-2025 world standard population. Spatial analyses were performed at department level for 1991-2017 using global and local Moran's Index, with queen contiguity weights and 999 permutations. Temporal trends were assessed with Joinpoint regression. Nationally, 165,251 deaths were recorded (crude rate 25·87 per 100,000 [95% Confidence Interval CI: 25·75-25·99]; ASMR 21·23 [95% CI: 21·12-21·34]). Truncated ASMR were 3·14 [95% CI: 3·09-3·19] for women <45 years and 67·98 [95% CI: 67·63-68·33] for women ≥45 years. Cuyo and Center showed higher ASMR (23·62 [95% CI: 23·19-24·05] and 22·07 [95% CI: 21·94-22·20], respectively) while Northwest had the lowest (16·58 [95% CI: 16·28-16·88]). ASMR declined in Argentina and most regions. Among women aged ≥45 years, declining patterns were observed in most regions, whereas among women aged <45 years trajectories were low and unstable, without sustained declines, and recent increases were identified in Northeast and Northwest. Spatial autocorrelation was pronounced for total ASMR and ≥45 years and weaker for <45 years (Moran's I 0·553, 0·550 and 0·133, respectively). High-high clusters concentrated in the Pampas corridor, whereas low-low clusters predominated in Northwest, parts of Northeast, and Patagonia. Breast cancer mortality in Argentina displays persistent territorial inequalities. Declining patterns were consistent among women aged 45 years and older, whereas heterogeneous and locally increasing patterns among women younger than 45 years, especially in northern regions, support prioritised subnational surveillance and further age-specific research. This study received no specific funding.