Examining Geographic Disparity: Variation in Cancer Outcomes Within Appalachia

BACKGROUND: The Appalachian region of the US extends from the Mississippi Delta to southern New York. Although disparities in Appalachian cancer outcomes have long been observed, recent rates and trends have not been assessed. STUDY DESIGN: We calculated 5-year age-adjusted US cancer incidence and mortality rates for 2017 to 2021, stratified into Appalachian and non-Appalachian populations, as well as Appalachian subregions, using the US Cancer Statistics Incidence Analytics Database and National Center for Health Statistics mortality files. Annual rates for 2004 to 2021 were also calculated. RESULTS: In 2017 to 2021, all-site cancer incidence (466.6; 95% CI 465.5 to 467.6) and mortality rates (165.5; 95% CI 164.9 to 166.1) among Appalachian residents were significantly higher (5.6% and 12.8%, respectively) than among non-Appalachian residents. Within Appalachia, the Central subregion-predominantly eastern Kentucky-had the highest rates of all-site cancer incidence (495.9) and mortality (201.9). In addition, the Central subregion had the highest rates of lung and colorectal cancer incidence, and the highest rates of lung, colorectal, and cervical cancer mortality. All-site cancer incidence and mortality rates among Appalachian individuals have decreased significantly since 2004 (-0.33% per year and -1.39% per year, respectively), with site-specific incidence rate decreases for late-stage lung (-2.19% per year), late-stage colorectal (-0.75% per year), and late-stage female breast (-0.35% per year) cancers in Appalachia. CONCLUSIONS: Although cancer incidence and mortality rates are declining in Appalachia, they remain substantially higher and demonstrate slower progress than elsewhere in the US-particularly in the Central Appalachian subregion-indicating the need for targeted research to delineate and address the factors driving these cancer health disparities.