Trends in colorectal cancer incidence rates by age, race/ethnicity, and indices of access to medical care, 1995–2004 (United States)

Colorectal cancer (CRC) incidence rates in the US decreased rapidly since 1998. This is largely thought to reflect increases in utilization of CRC screening through detection and removal of adenomatous polyps. However, the extent to which the decrease varies by age, race/ethnicity, and differences in access to medical care is largely unknown.

Temporal trends in CRC incidence rates were examined from 1995 to 2004 by regression analysis according to age (50–64, ≥65), race/ethnicity (whites, African Americans, and Hispanics), and categories of county-level indicators of access to care (poverty, primary care physician supply [PCP], uninsured rate [age 50–64], and metro/nonmetro) using incidence data from 19 cancer registries, covering about 53% of the US population. Changes in colorectal endoscopic screening and fecal occult blood stool test (FOBT) from 1995–1997 to 2002–2004 for the same set of county-level indicators were also analyzed, using data from the Behavioral Risk Factor Surveillance System (BRFSS).

Among whites, CRC incidence rates decreased significantly from 1998 through 2004 in age ≥65, but not in age 50–64 in counties with high uninsured or poverty rates, fewer PCPs, or in nonmetro areas. Among African Americans or Hispanics, rates did not decrease in age 50–64 in general and age ≥65 in counties with high poverty rates, low PCP supply, and nonmetro counties (African Americans). Colorectal endoscopic screening rates increased significantly among whites in both age groups, but not among Hispanics (aged 50–64 in general and aged ≥65 residing in high poverty counties) or African Americans residing in counties with higher uninsured rates (age 50–64), low PCP supply, high poverty rates, and nonmetro counties (age ≥ 65). FOBT rates remained unchanged during the study time period.

Our results suggest that individuals residing in poorer communities with lower access to medical care have not experienced the reduction in CRC incidence rates that have benefited more affluent communities; these disparities may be related to health care access barriers to colorectal endoscopic screening.