In an analysis reported in a letter to the editor in The New England Journal of Medicine, Doubeni et al found that a sustained Kaiser Permanente Northern California (KPNC) colorectal cancer screening initiative resulted in increased screening, increased identification of colorectal cancer, and a reduction in colorectal cancer mortality among Black individuals that dramatically reduced the disparity in colorectal cancer mortality between White and Black patients.
Study Details
The analysis evaluated the association between participation in colorectal cancer screening and age-standardized incidence rates and mortality from 2000 through 2019 among Black and White persons aged 50 to 75 years who were members of the KPNC health plan, with follow-up extended through age 79. From 2006 to 2008, KPNC initiated—and has since maintained—an organized, population-based colorectal cancer screening program, including proactive mailing of fecal immunochemical testing annually and on-request colonoscopy.
Key Findings
The analysis cohort increased to 88,734 Black persons and 703,347 White persons by 2019. The proportions of individuals who were up to date with screenings increased from 42% in 2000 to 79% to 80% in 2015 to 2019 among Black persons, and from 40% to 82% to 83% over the same periods among White persons.
The incidence of colorectal cancer expressed as a 3-year rolling average increased from 122 cases per 100,000 population in 2002 to 166/100,000 in 2010 among Black persons. Among White persons, the incidence was 118/100,000 in 2002 and relatively stable until 2007, with an increase to 135/100,000 in 2009. The incidence thereafter decreased to 78/100,000 among Black persons and to 82/100,000 among White persons in 2017 to 2019.
The incidence of early-stage disease initially increased in both Black and White persons, followed by decreases in both early- and late-stage disease in both groups. Both the initial increase in early-stage disease and later decreases in early- and late-stage disease were greater among Black persons.
Colorectal cancer–specific mortality decreased from 54 cases/100,000 in 2007 to 2009 to 21 cases/100,000 in 2017 to 2019 among Black patients, and from 33/100,000 to 20/100,000 in White patients over the same periods. Over this time, the absolute between-group difference in colorectal cancer mortality decreased from 21.6 cases/100,000 (95% confidence interval [CI] = 9.8–33.5 cases/100,000) to 1.6 cases/100,000 (95% CI = −4.9 to 8.1 cases/100,000).
The investigators concluded, “These results occurred within a health-care system that serves patients who closely approximate the region’s underlying population, including people insured by Medicaid and Medicare, and thus support the principle that sustained efforts to intentionally enable equitable delivery of effective interventions across the care continuum can decrease, or even eliminate, related health disparities over time.”
Disclosure: The study was supported by grants from the National Cancer Institute. For full disclosures of the study authors, visit nejm.org.
