Disparities in colorectal cancer incidence and mortality in Appalachian Kentucky.

Abstract

e15673 Background: Since the late 1990s, both the incidence and mortality of invasive colorectal cancer (CRC) have decreased across the United States, including in Kentucky. Despite this, CRC incidence and mortality are above national average in Kentucky. Over the last two decades, a disparity in CRC incidence and mortality has emerged between Appalachian Kentucky (AK), a distinct eastern region, and Non-Appalachian Kentucky (NAK). This disparity is attributed to differences in social and structural determinants of health (SSDH) between these populations. Methods: Age-adjusted CRC incidence and mortality rates (2016-2020) for both Kentucky and the U.S. were obtained from the National Cancer Institute’s public database. Data from the Kentucky Cancer Registry were used to compare CRC incidence and mortality rates in AK and NAK counties from 1994-2021. Incidence rate ratio analyses across discrete time periods demonstrated statistical differences between these regions. Results: Compared to national data (2016-2020), Kentucky's CRC age-adjusted incidence and mortality rates were significantly higher: 45.9 vs. 36.5/100,000, 25.8%, for incidence, and 16.2 vs. 13.1/100,000, 23.7%, for mortality (both p < 0.0001). From 1995-2003 incidence and 1994-2003 mortality of CRC, were higher in NAK, these rates eventually decreased and equalized between NAK and AK. By 2010-2015 both incidence and mortality rates were higher in AK, 55.8 vs 48/100,000, 16.3%, (p = < 0.0001) and 20.1 vs 15.8/100,000, 27.2%, (p = < 0.0001) respectively. The most recent data (2016-2021) shows that these significant disparities persist, with AK’s incidence and mortality 51.8 vs 44.1/100,000, 17.5% (p = < 0.0001) and mortality 19.0 vs 15.1/100,000, 25.8% (p = < 0.0001) higher, respectively. Conclusions: While CRC rates have decreased nationwide and in Kentucky, a pronounced gap in both incidence and mortality has developed between Appalachian and Non-Appalachian Kentucky. Appalachian counties—which are more rural and impoverished—face greater barriers to accessing preventive healthcare, contributing to this disparity. Additionally, AK has higher rates of obesity, poverty, smoking, and lower educational attainment and screening rates. Recent public health efforts, such as promoting stool-based screening and increasing preventive care discussions, aim to reduce these disparities. However, delays in CRC screenings during the COVID-19 pandemic— resulting in approximately 1.7 million missed colonoscopies nationally— may have skewed the most recent data, necessitating further analysis in the coming years.