Abstract Introduction: Lower gastrointestinal (GI) cancers, including jejunal, ileal, colorectal and anal malignancies, remain among the most prevalent cancers in the United States. According to data from the Internal Agency for Research on Cancer (IARC), lower GI cancers accounted for roughly 10% of newly diagnosed cancers and over 9% of all cancer mortality in adults in 2022. However, trends in lower GI cancer mortality vary by geographic region and race. Understanding these disparities can support equitable cancer prevention strategies and targeted public health interventions. Methods: Age-adjusted mortality rates from 1999 to 2020 were extracted from the CDC Wide-ranging Online Data for Epidemiologic Research (WONDER) database and analyzed using Joinpoint regression to identify temporal changes in lower GI cancer mortality by U.S. Census region and racial/ethnic group. Lower GI cancers were defined using ICD-10 codes C17.1-C21, which included all malignant neoplasms from the jejunum to the anus. Annual percent change (APC) and average annual percent change (AAPC) were calculated and Age-Adjusted mortality rates were compared, with statistical significance set at p 0.05. Results: All four census regions demonstrated statistically significant declines in lower GI cancer mortality over the study period. The steepest average decline was observed in the Northeast (AAPC = -3.06%, 95% CI: -3.54 to -2.57; p 0.0001), followed by the Midwest (-2.32%, 95% CI: -2.46 to -2.17), West (-2.05%, 95% CI: -2.23 to -1.87), and South (-2.01%, 95% CI: -2.17 to -1.84). Significant declines in mortality rates were also seen across all racial and ethnic groups. The largest decrease occurred among Black or African American individuals (AAPC = -2.70%, 95% CI: -2.88 to -2.53), followed by White individuals (AAPC = -2.13%), Asian or Pacific Islander (-1.92%), Hispanic or Latino (-1.58%), and American Indian or Alaska Native (-1.67%). The White cohort exhibited multiple Joinpoints, with an initial sharp decline between 2002–2005 (APC = -3.70%), followed by a continued decline through 2020. However, despite statistically significant decreases in lower GI cancer mortality rates during the observed time-period, Black or African American mortality rates were significantly higher than those in all other races. Conclusions: Lower GI cancer mortality has declined significantly across racial and regional lines in the United States, though the magnitude of reduction varies. Northeastern states and Black individuals experienced the steepest improvements; however Black or African American populations have persistent and significantly increased mortality rates than all other races. Continued focus on early detection, racial, and region-specific public health initiatives is essential to sustain and enhance these positive trends, particularly in regions or groups with slower declines and persistently higher mortality rates. Citation Format: Shefali Khanna, FNU Rashi, Muhammad Ahmed, Bianca Mannariat, Jonathan Lopez. Trends in lower gastrointestinal cancer mortality across racial and regional groups in the United States: A CDC WONDER and Joinpoint trend analysis, 1999–2020 abstract. In: Proceedings of the 18th AACR Conference on the Science of Cancer Health Disparities; 2025 Sep 18-21; Baltimore, MD. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2025;34(9 Suppl):Abstract nr C008.
Khanna et al. (Thu,) studied this question.