Cardiovascular Mortality Risk After Cancer Diagnosis by County-Level Characteristics in the United States 2000-2021.

BACKGROUND: Advances in cancer therapy have improved survival, but cardiovascular disease (CVD) is now the leading non-cancer cause of death among survivors. Specialized cardio-oncology care mitigates risk, yet access remains limited outside of urban academic centers. METHODS: We conducted a retrospective cohort study using Surveillance, Epidemiology, and End Results (SEER) 17 Registries (2000-2021), including 6,467,098 individuals with first primary malignancies. Outcomes were CVD-specific mortality, estimated using standardized mortality ratios (SMRs) and excess absolute risks (EARs). Exposures were county-level urban/rural status, persistent poverty status, and racial composition. Cancer-specific analyses were additionally performed for major cancer sites to assess heterogeneity in county-level disparities. RESULTS: During follow-up, 394,540 CVD deaths occurred (SMR = 1.11; 95% CI = 1.11, 1.11). Survivors in rural counties (SMR = 1.27), counties with persistent poverty (SMR = 1.35), and those with the highest quartile of Black residents (SMR = 1.15) had significantly higher CVD mortality compared with the general population. The highest risk was observed in rural counties with persistent poverty (SMR = 1.53). Across county groups, CVD mortality peaked within the first year after diagnosis and remained elevated for over a decade in disadvantaged communities. Substantial heterogeneity was found across cancer types in county-level disparities in CVD mortality, with the largest EAR differences observed among survivors of lung and bronchus cancer, followed by corpus uteri, prostate, and urinary bladder cancers. CONCLUSIONS: Cancer survivors experience substantial and sustained excess CVD mortality, with the greatest disparities in rural and persistently impoverished counties. These findings highlight the need to integrate cardiovascular surveillance into survivorship care and expand access to cardio-oncology services in socially vulnerable communities.