County-level colorectal cancer screening rates on colorectal cancer survival in the state of Georgia: Does county-level rurality matter?

Abstract

Investigating CRC screening rates and rurality at the county-level may explain disparities in CRC survival in Georgia. Although a few studies examined the relationship of CRC screening rates, rurality, and/or CRC outcomes, they either used an ecological study design or focused on the larger population. We conducted a retrospective analysis utilizing data from the 2004-2010 Surveillance, Epidemiology, and End Results Program. The 2013 United States Department of Agriculture rural-urban continuum codes and 2004-2010 National Cancer Institute small-area estimates for screening behaviors were used to identify county-level rurality and CRC screening rates. Kaplan-Meier method and Cox proportional hazard regression were performed. Among 22,160 CRC patients, 5-year CRC survival rates were lower among CRC patients living in low screening areas in comparison with intermediate/high areas (69.1% vs. 71.6% /71.3%; p-value = 0.030). Patients living in rural high-screening areas also had lower survival rates compared to non-rural areas (68.2% vs. 71.8%; p-value = 0.009). Our multivariable analysis demonstrated that patients living in intermediate (HR, 0.91; 95% CI, 0.85-0.98) and high-screening (HR, 0.92; 95% CI, 0.85-0.99) areas were at 8%-9% reduced risk of CRC death. Further, non-rural CRC patients living in intermediate and high CRC screening areas were 9% (HR, 0.91; 95% CI, 0.83-0.99) and 10% (HR, 0.90; 95% CI, 0.82-0.99) less likely to die from CRC. Lower 5-year survival rates were observed in low screening and rural high-screening areas. Living in intermediate/high CRC screening areas was negatively associated with the risk of CRC death. Particularly, non-rural patients living in intermediate/high-screening areas were 8%-9% less likely to die from CRC. Targeted CRC screening resources should be prioritized for low screening and rural communities.