253 Geographic Early-Onset Colorectal Cancer Incidence Rate Disparities Within White and African American Populations in the United States

Abstract

INTRODUCTION: Prior study by our group revealed marked geographic disparities in early-onset colorectal cancer (EOCRC) incidence rates (IR) (Abualkhair et al. abstract #984 DDW 2019). Although it is established CRC IRs in African Americans are higher than whites, there is paucity of data on geographic EOCRC disparities within both white and African American populations. Hence, we seek to explore the role race may play in IR differences between U.S. regions and individual registries. METHODS: 2000–2015 SEER 18 CRC IR Analysis (170,434 cases) was performed in one-year age increments (ages 30–60) in four U.S. regions, individual registries and stratified by race. RESULTS: There are wide regional IR disparities at multiple ages within both white and African American populations. For example, at age 45, there is a 52% difference (P < 0.05) between the highest (south) and lowest (west) regional IRs in African Americans compared to a 32% difference (P < 0.05) in whites (Figures 1 and 2). At multiple age points <50, there is a trend for greater disparity between the highest and lowest regional IRs within the African American population compared to within the white population (shaded boxes in Figure 2) however these did not reach statistical significance at most ages. CONCLUSION: There are marked geographic EOCRC IR disparities within white and African American populations between U.S. regions. There appears to be a trend toward more pronounced geographic disparities within the African American population, however interpretation is limited by lack of statistical significance at multiple age points, likely due to lower case counts. Targeting all populations is critical for CRC prevention, however we must assure attention is paid to higher-risk populations. Potential interventions include targeted risk factor modifications, assuring concerning symptoms trigger prompt diagnostic evaluations and taking advantage of earlier age 45 screening options supported by some guidelines (USMSTF recommends screening African Americans at age 45 and ACS recommends average-risk screening of all patients at age 45). By identifying higher-risk populations, future targeted studies can also be performed which may allow better understanding of rising EOCRC rates.