The need to study rural cancer outcome disparities at the local level: a retrospective cohort study in Kansas and Missouri

• Type of Material: Article
• Authors: Jeffrey A Thompson, University of Kansas; Lynn Chollet-Hinton, University of Kansas; John Keighley, University of Kansas; Audrey Chang, Emory University; Dinesh Pal Mudaranthakam, University of Kansas; David Streeter, University of Kansas; Jinxiang Hu, University of Kansas; Michele Park, University of Kansas; Byron Gajewski, University of Kansas
• Language: English
• Date: 2021-11-24
• Publisher: BMC
• Publication Version: Final Published Version
• Copyright Statement: © The Author(s) 2021
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1186/s12889-021-12190-w
• Title of Journal or Parent Work: BMC PUBLIC HEALTH
• Volume: 21
• Issue: 1
• Start Page: 2154
• End Page: 2154
• Grant/Funding Information: This work was supported by the National Cancer Institute (NCI) Cancer Center Support Grant P30 CA168524, and the Kansas Institute of Precision Medicine COBRE P20GM130423. The funding bodies had no role in the design of the study; the collection, analysis, and interpretation of the data; or the preparation of the manuscript.
• Keywords: Rurality; Science & Technology; URBAN; Life Sciences & Biomedicine; Cancer; SURVIVAL; UNITED-STATES; CARE; Healthcare disparities; STAGE; Public, Environmental & Occupational Health; Socioeconomic factors; RESIDENCE; DISEASE; MORTALITY
• Research Categories: Health Sciences, Oncology; Biology, Biostatistics

Abstract

Background: Rural residence is commonly thought to be a risk factor for poor cancer outcomes. However, a number of studies have reported seemingly conflicting information regarding cancer outcome disparities with respect to rural residence, with some suggesting that the disparity is not present and others providing inconsistent evidence that either urban or rural residence is associated with poorer outcomes. We suggest a simple explanation for these seeming contradictions: namely that rural cancer outcome disparities are related to factors that occur differentially at a local level, such as environmental exposures, lack of access to care or screening, and socioeconomic factors, which differ by type of cancer. Methods: We conducted a retrospective cohort study examining ten cancers treated at the University of Kansas Medical Center from 2011 to 2018, with individuals from either rural or urban residences. We defined urban residences as those in a county with a U.S. Department of Agriculture Urban Influence Code (UIC) of 1 or 2, with all other residences defines a rural. Inverse probability of treatment weighting was used to create a pseudo-sample balanced for covariates deemed likely to affect the outcomes modeled with cumulative link and weighted Cox-proportional hazards models. Results: We found that rural residence is not a simple risk factor but rather appears to play a complex role in cancer outcome disparities. Specifically, rural residence is associated with higher stage at diagnosis and increased survival hazards for colon cancer but decreased risk for lung cancer compared to urban residence. Conclusion: Many cancers are affected by unique social and environmental factors that may vary between rural and urban residents, such as access to care, diet, and lifestyle. Our results show that rurality can increase or decrease risk, depending on cancer site, which suggests the need to consider the factors connected to rurality that influence this complex pattern. Thus, we argue that such disparities must be studied at the local level to identify and design appropriate interventions to improve cancer outcomes.