Abstract 3552: Geographic and sociocultural disparities in breast cancer incidence and mortality in Latin America: Joinpoint trend analysis with a focus on regional variations within Colombia

Abstract Background: Breast cancer (BC) remains the leading cause of cancer-related mortality among females worldwide. BC is the most common malignancy and cancer-related death among women in Latin America and the Caribbean (LAC), with substantial heterogeneity across the region. While overall BC burden continues to rise, geographic, demographic, and sociocultural disparities shape outcomes. Subnational analysis within countries such as Colombia is essential to identify context-specific challenges and opportunities for targeted interventions. Methodology: We analyzed data from some of the most burdened countries in Latin America and compared them to the United States to quantify temporal trends in breast cancer (BC) incidence and mortality. Particular attention was given to subnational regions within Colombia. Using national and regional cancer registry sources and Joinpoint regression analysis to estimate annual (APC) and average annual percent change (AAPC) in incidence and mortality, Age-block analyses were performed to compare incidence by country and age group (Early adult, Adult, Later adult). Descriptive and ecological multivariable analyses explored associations with geographic, demographic, and sociocultural variables. We sought to relate these epidemiological trends to geographic, demographic (population structure), cultural, and lifestyle determinants, aiming to identify key correlations that may explain the variability in BC burden observed both between and within countries. Results: Incidence and mortality rates increased with age across all countries. USA and Argentina exhibited the highest incidence among older adults, while Colombia had the lowest rates. Statistically significant differences in BC incidence were observed among countries in the adult and later adult age blocks (Kruskal-Wallis p < 0.001), but not among early adults. Joinpoint regression identified variation in the timing and magnitude of trend changes (joinpoints) between countries and within Colombian cities, with divergent patterns often corresponding to urbanization, socioeconomic status, and access to screening. Multivariable analyses revealed that regional disparities in incidence and mortality correlated more strongly with geographic, demographic, and lifestyle factors than with genetic ancestry. Conclusions: Marked international and subnational disparities in BC incidence and mortality underscore the influence of geography, population structure, and sociocultural context in Latin America. Findings support the need for tailored public health strategies, emphasizing targeted screening and equitable access to care. Citation Format: Oscar Marino Vidal., . Geographic and sociocultural disparities in breast cancer incidence and mortality in Latin America: Joinpoint trend analysis with a focus on regional variations within Colombia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3552.