(P52) Rural-Urban Continuum as a Potential Geographic Correlate of Breast and Prostate Cancer Mortality in Nevada

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International Journal of Radiation Oncology Biology Physics





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Introduction Data suggest that incidence and mortality associated with breast and prostate cancer have shown favorable trends through time, wherein data for the US show decreasing trends in these measures, except for breast cancer incidence, which has plateaued since 2003. Examination of Nevada data, however, suggests that mortality for both cancers is slightly higher than the US average. Further, mortality rates for metro vs non-metro areas suggest potential geographic disparities in mortality. The objective of this investigation was to examine purported differences in metro, urban, and rural counties in Nevada as potential geographic correlates of cancer mortality. Materials/Methods Data for breast and prostate cancer for Nevada were obtained from two sources: (1) statewide incidence and mortality were from the CDC’s United States Cancer Statistics Incidence and Mortality reports (1999-2014); and (2) county-based mortality was obtained from the Institute for Health Metrics and Evaluation, Global Health Data Exchange (1980-2014). Additional data on decadal Rural-Urban Continuum (RUCC) codes were obtained from SEER for decades starting in 1974 through 2013, and these were matched to counties in Nevada to obtain a temporal representation of cancer mortality as a function of metro, urban, or rural status to develop correlative associations of geography and mortality rates. Mortality distributional curves were compared using a Bonferroni-adjusted Kolmogorov-Smirnov test among the three geographic designations. Results Similar to the US average, both breast and prostate cancer incidence and mortality demonstrated a general temporal decline regardless of geography. For breast cancer, mortality did not differ between metro and urban counties (D = 1.01, p = .771), but both exceeded rural counties (D = 1.75, = .012; D = 2.30, p < .001), respectively. All geographic areas showed a plateau or slight increase in the most recent years of data, wherein rural mortality rates exceeded metro in 2013-2014. For prostate cancer, mortality rates for urban counties always exceeded metro and rural counties (D = 3.56, p < .001; D = 3.52, p < .001), respectively, though metro and urban rates did not differ (D = 1.40; p = .117). Similar to breast cancer, there were increases across all geographies in the most recent years of data, with rural mortality rates exceeding metro from 2010-2014. Conclusions Geography may play a significant role in the incidence and mortality of certain cancers, particularly for patients who are located in areas with fewer medical resources for screening and/or treatment. This potentially results in increased mortality rates associated with treatment of late-stage disease that may not be predicated by increased morbidity estimates for those without ready access to screening and treatment. Further, mortality estimates may seem paradoxically higher in metro and urban areas compared to rural areas because patients likely travel to these geographies to obtain care, hence potentially increasing mortality estimates for these areas. This study provides some evidence of the importance of considering rural-urban continuum in exploring incidence and mortality rates for cancer, and provides an initial exploration of data relevant for understanding health disparities related to geography for the population of Nevada.





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