Widening racial and rural disparities in colorectal cancer mortality in Wisconsin: A population-based analysis, 1999–2020.

Abstract

231 Background: Colorectal cancer (CRC) is one of the leading causes of cancer-related death in the United States; nevertheless, significant differences exist among racial and geographic populations. Current statewide data demonstrating these disparities in Wisconsin are scarce. Methods: Age-adjusted CRC mortality rates (AAMRs) for Wisconsin residents were sourced from the CDC WONDER Underlying Cause of Death database (1999–2020) utilizing ICD-10 codes C18–C20. Analyses were categorized by race/ethnicity and urban-rural classification. Joinpoint regression calculated annual percent changes (APCs), and Black-White mortality rate ratios were determined across time. The mortality of early-onset colorectal cancer (ages 25–54 years) was assessed using aggregated 5-year intervals. Results: CRC mortality decreased in both racial categories, but the decline was more pronounced among White non-Hispanic individuals (APC −2.82%/year, p<0.001) compared to Black non-Hispanic individuals (APC −1.50%/year, p=0.028). In 2020, the AAMRs were 22.4 and 10.8 per 100,000, respectively. The Black-White death rate ratio rose from 0.94 in 1999 to 2.07 in 2020. Rural counties exhibited significantly elevated pooled colorectal cancer mortality compared to large urban counties (42.6 vs. 15.2 per 100,000). Mortality from early-onset colorectal cancer (CRC) rose among White non-Hispanic individuals (APC +1.47%/year, p=0.005), while Black non-Hispanic mortality consistently remained nearly double that of Whites throughout the research duration. Conclusions: Wisconsin's Black–White CRC mortality disparity has grown over the past two decades, with Black residents facing more than twice the mortality rate of White residents by 2020 despite overall decreases. Rural Wisconsinites, especially in the northwest, have higher mortality rates, and younger White persons are developing CRC earlier. Community-based and mobile colonoscopy programs in high-deprivation rural counties, Medicaid-supported screening for underinsured Black populations in urban centers, and the updated USPSTF guidelines lowering screening initiation to age 45 for all populations are needed to address these inequities. Wisconsin oncology care must track disparities' trajectories, not just rates.