Racial and Geographical Disparities in Colorectal Cancer Incidence in Mississippi, 2003-2018

Purpose: The aim of this study is to investigate racial and geographical disparities of colorectal cancer incidence in Mississippi. Methods: Incidence data from 2003-2018 were obtained at the county-level from the Mississippi Cancer Registry. Incidence rate difference and 95% confidence intervals between age-adjusted colorectal cancer incidence for whites and blacks were calculated and mapped using ArcGIS. Results: The black incidence rate for colorectal cancer was 59.8 per 100,000 while the white incidence rate was 48.9 per 100,000. Blacks experienced significantly higher incidence rates than whites in 39 counties throughout much of Mississippi. These areas of higher racial disparities did not cluster in a specific region of the state. In the southern part of the state an 8-county cold-spot region was detected without racial disparities; incidence rate for blacks was 41.3 per 100,000 in this region. Conclusions: There are racial disparities throughout Mississippi except for an 8-county region towards the southern part of the state. Additional research should be conducted to identify what factors are responsible for the lower incidence rates among blacks in this region, and to implement effective interventions statewide to reduce racial disparities in colorectal cancer incidence.

The impact of cumulative colorectal cancer screening delays: A simulation study

Objective Annual fecal immunochemical tests can reduce colorectal cancer incidence and mortality. However, screening is a multi-step process and most patients do not perfectly adhere to guideline-recommended screening schedules. Our objective was to compare the reduction in colorectal cancer incidence and life-years gained based on US guideline-concordant fecal immunochemical test screening to scenarios with a range of delays. Method The Colorectal Cancer Simulated Population model for Incidence and Natural history (CRC-SPIN) microsimulation model was used to estimate the effect of systematic departures from fecal immunochemical test screening guidelines on lifetime screening benefit. Results The combined effect of consistent modest delays in screening initiation (1 year), repeated fecal immunochemical test screening (3 months), and receipt of follow-up or surveillance colonoscopy (3 months) resulted in up to 1.3 additional colorectal cancer cases per 10,000, 0.4 additional late-stage colorectal cancer cases per 10,000 and 154.7 fewer life-years gained per 10,000. A 5-year delay in screening initiation had a larger impact on screening effectiveness than consistent small delays in repeated fecal immunochemical test screening or receipt of follow-up colonoscopy after an abnormal fecal immunochemical test. The combined effect of consistent large delays in screening initiation (5 years), repeated fecal immunochemical test screening (6 months), and receipt of follow-up or surveillance colonoscopy (6 months) resulted in up to 3.7 additional colorectal cancer cases per 10,000, 1.5 additional late-stage colorectal cancer cases per 10,000 and 612.3 fewer life-years gained per 10,000. Conclusions Systematic delays across the screening process can result in meaningful reductions in colorectal cancer screening effectiveness, especially for longer delays. Screening delays could drive differences in colorectal cancer incidence across patient groups with differential access to screening.