Black and White Differences in Colorectal Cancer Screening and Screening Outcomes: A Narrative Review

Abstract

Racial disparities in colorectal cancer incidence are widely documented. There are two potential mechanisms for these disparities: differences in access to screening, including screening follow-up, and differences in underlying risk of colorectal cancer. We reviewed the literature for evidence of these two mechanisms. We show that higher colorectal cancer incidence in blacks relative to whites emerged only after the dissemination of screening and describe evidence of racial disparities in screening rates. In contrast to the strong evidence for differences in colorectal cancer screening utilization, there is limited evidence for racial differences in adenoma prevalence. In general, black and white patients who are screened have similar adenoma prevalence, though there is some evidence that advanced adenomas and adenomas in the proximal colon are somewhat more likely in black than white patients. We conclude that higher rates of colorectal cancer incidence among black patients are primarily driven by lower rates of colorectal cancer screening. Our findings highlight the need to increase black patients' access to quality screening to reduce colorectal cancer incidence and mortality.

Figure 1.

Colorectal cancer incidence per 100,000 by race from 1975–2017. Datapoints are from the SEER 9 Registry and the trend line is from a Joinpoint regression analysis.

Figure 2.

Colorectal cancer incidence per 100,000 by race and time period, from the SEER 9 Registry.