April 26, 2022

A Mayo Clinic physician conducted a study, published in the February 2022 New England Journal of Medicine, to evaluate the effects on health disparities of delivering colorectal cancer screening in a consistent way across an entire health system. The study found that not only did the health system improve screening and reduce deaths for colorectal cancer, but it also eliminated racial disparities for colorectal cancer in the system.

"It's all about the system," said Chyke A. Doubeni, M.B.B.S., M.P.H., a clinical epidemiologist and health services researcher at Mayo Clinic in Arizona. Dr. Doubeni says that expecting individuals to do something is one way to make things fall through the cracks. Creating systems provides support. "Having effective systems that are not dependent entirely on individuals is critical."

The study evaluated the association between participation in colorectal cancer screening and age-standardized incidence rates and mortality among non-Hispanic Black patients and non-Hispanic white patients. All patients were members of Kaiser Permanente Northern California (KPNC) and between the ages of 50 and 79 years old. Data were collected from 2000 to 2019.

Complete and consistent colorectal cancer screening

KPNC initiated and has since sustained the screening program evaluated in this study. The population-based program uses mailed fecal immunochemical testing (FIT) annually as the primary screening test in addition to screening colonoscopy when requested. The FIT kits are mailed proactively to people who are due for screening to eliminate potential barriers associated with having to see a physician prior to getting screened.

Being a systemwide program, KPNC has implemented monitoring practices from screening through follow-up and treatment if necessary. The system tracks who is due for screening, as well as screening completion, results, and diagnostics and follow-up if needed.

"Immediately we bypassed the need for somebody to be in front of a doctor before they could get screened," said Dr. Doubeni. "When Kaiser found that some people were lagging, they tried various strategies. It was not a static thing. They kept improving the processes over time to make it work better."

As part of the ongoing program, patients are reminded about screening at any touchpoint they have with the system, regardless of whether a formal visit with a physician is involved.

Mortality and screening and treatment rates

Screening and incidence rates and mortality were evaluated throughout the course of the study for both Black and white patients. The percentage of those up to date on screenings saw relatively consistent increases regardless of race. In 2000, 42% of Black patients and 40% of white patients were up to date on screening for colorectal cancer. From 2015 to 2019, those rates rose to 79% to 80% and 82% to 83%, respectively.

Closing the care gap for racial disparities in colorectal cancer

As expected, the incidence of colorectal cancers in both groups increased initially followed by decreases in both early- and late-stage cancers. Both the initial increase and the later decrease were greater among Black patients.

Similarly, mortality decreased in both groups with a larger decrease for Black patients. Measured on a three-year rolling average, initial mortality from 2007 to 2009 for Black patients and white patients was 54 cases per 100,000 and 33 cases per 100,000, respectively. This initial mortality measurement reflects similar national patterns of higher mortality from colorectal cancer for Black patients than other racial groups.

From 2017 to 2019, however, mortality for Black patients was 21 cases per 100,000 and for white patients was 20 cases per 100,000. The improvements in equitable delivery of screening, diagnostics and follow-up for colorectal cancer showed greater benefits among Black patients likely due to their higher baseline incidence and mortality.

Closing the gap for racial health disparities

This study shows that a centralized proactive process for screening that includes monitoring of progress and appropriate timely access to follow-up services improves screening rates. It also shows that this type of equitable program delivery can close care gaps between Black and white patients.

"Some say these racial differences are associated with genetics and biology," said Dr. Doubeni. "The research that we have done has convinced me that it's not due to inherent genetic differences."

Improved screening rates are incredibly important in addressing colorectal cancer. Monitoring those screened throughout a health care system and providing equitable care that is not dependent on patients being seen by a physician can address the health disparities we often see associated with race for colorectal cancer.

For more information

Doubeni C, et al. Association between improved colorectal screening and racial disparities. New England Journal of Medicine. 2022;386:796.

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