6D-07 - Geographic, Racial, and Ethnic Disparities in Colorectal Cancer Mortality in Adults 45+ living in the United States, 2000-19

Background: Colorectal cancer (CRC) is the third most common cancer and the third leading cause of cancer-related death in the United States. A nuanced understanding of CRC mortality rates and disparities at the county level is needed to identify high-risk populations and places for clinical trial planning and benchmarking.

Objectives: To estimate age-standardized, county-level CRC mortality estimates from 2000-2019 for adults aged 45+, stratified by sex and race and/or ethnicity.

Methods: We applied validated small-area estimation methods to death registration data from the US National Vital Statistics System and population data from the US National Center for Health Statistics to estimate CRC mortality rates by county, race and/or ethnicity, age, and sex from 2000-19. Estimates were corrected for misreporting of race and/or ethnicity on death certificates and age-standardized to the 2010 Census.

Results: Nationally, CRC mortality rates fell from 82.5 (95% uncertainty interval [UI] 81.7-83.2] to 54.4 deaths (53.9-54.9) per 100,000 among males 45+ and from 58.9 deaths (58.4-59.3) to 39.7 deaths (39.4-40.0) per 100,000 among females between 2000 and 2019. The most substantial declines were observed among Black females (absolute difference -31.8 deaths [-33.8 to -30.0] per 100,000) and males (-42.9 deaths [-45.9 to -39.7] per 100,000). Despite experiencing the largest declines, Black males and females still had the highest mortality rates in 2019 within each sex group, respectively. Most counties also experienced declines in CRC mortality from 2000-19; however, a substantial proportion of counties saw rates increase among American Indian or Alaska Native (AIAN) females (21.5%; median absolute increase 4.3 deaths [IQR 1.5-7.9] per 100,000), AIAN males (20.9%; 7.3 [3.0-13.7] deaths per 100,000), and Latino males (15.0%; 2.5 deaths [1.2-4.4] per 100,000). Almost half of counties where CRC mortality increased among AIAN females (48.0%) and males (43.4%) were in Oklahoma; 36.2% of counties with increased CRC mortality rates among Latino males were in North and South Carolina. In 2019, there were 275 unique counties with CRC mortality rates >100 deaths per 100,000 for one or more populations (Black males: 182 counties; AIAN males: 92; AIAN females: 13; White males: 4; Latino males: 1).

Conclusions: Nationally, significant improvements in CRC mortality have occurred from 2000 to 2019. However, county-level estimates tell a different story, showing that some populations and places are being left behind in CRC progress. These findings provide critical information not found in national estimates for those planning CRC clinical trials and can support population-representative enrollment efforts.