Rural reversal? Rural-urban disparities in late-stage cancer risk in Illinois.

Abstract

Differences in late-stage cancer risk between urban and rural residents are a key component of cancer disparities. Using data from the Illinois State Cancer Registry from 1998 through 2002, the authors investigated the rural-urban gradient in late-stage cancer risk for 4 major types of cancer: breast, colorectal, lung, and prostate. Multilevel modeling was used to evaluate the role of population composition and area-based contextual factors in accounting for rural-urban variation. Instead of a simple binary rural-urban classification, a finer grained classification was used that differentiated the densely populated City of Chicago from its suburbs and from smaller metropolitan areas, large towns, and rural settings. For all 4 cancers, the risk was highest in the most highly urbanized area and decreased as rurality increases, following a J-shaped progression that included a small upturn in risk in the most isolated rural areas. For some cancers, these geographic disparities were associated with differences in population age and race; for others, the disparities remained after controlling for differences in population composition, zip code socioeconomic characteristics, and spatial access to healthcare. The observed pattern of urban disadvantage emphasized the need for more extensive urban-based cancer screening and education programs.