Rural and racial disparities in colorectal cancer incidence and mortality in South Carolina, 1996-2016

Purpose Colorectal cancer (CRC) is the third leading cause of cancer mortality among men and women in the United States and South Carolina (SC). Since SC has one of the highest proportions of Black (27.9%) and rural residents (33.7%), the purpose of this investigation was to describe the burden of CRC on racial disparities in rural populations. Methods Count data from 2012 to 2016 were obtained from the state central cancer registry using an online data retrieval system. Rural-urban status was determined using Urban Influence Codes (1-2 = urban; 3-12 = rural). Chi-square tests were calculated to examine differences in CRC stage by rurality and race. Annual percent change and annual average percent change (AAPC) were calculated to examine trends in incidence and mortality rates across rural-urban and racial groups between 1996 and 2016. Results Areas with high mortality-to-incidence ratios tended to be in rural counties. Furthermore, rural residents had higher proportions of distant stage CRC compared to urban residents, and Black populations had higher proportions of distant stage CRC compared to White populations (22.7% vs. 26.3% and 29.3% vs. 23.7%, respectively; P value < 0.05). From 1996 to 2016, Black and White urban-dwelling residents experienced a significant decline in incidence. Urban White, urban Black, and rural White populations experienced significant declines in mortality (AAPC = -2.6% vs -2.4% vs -1.6% vs -0.9%, respectively). Conclusions Despite improvements in CRC screening in recent decades, focused evidenced-based interventions for lowering incidence and mortality among rural and Black populations in South Carolina are necessary.