Closing the Racial Gap in CRC: Screening is Just the First Step

Too many people in the United States are dying of colorectal cancer (CRC). The #2 cancer killer in the United States, it impacts Black Americans disproportionately. Compared to White adults, Black adults aged 50 and above get colon cancer at a rate that’s 23% higher than White adults and have a 31% higher risk of dying from the disease.¹ These disparities persist despite progress in screening and treatment and are particularly frustrating because CRC is highly treatable when caught in early stages and even preventable when pre-cancers are identified and removed through screening. These differences in incidence and mortality persist even while we have made progress to make screening more accessible to all. A 2019 NIH study showed that a similar proportion of Black and White Americans are up to date with CRC screening², a meaningful improvement since 2005³. If screening access and uptake are now so similar, why do these disparities persist?  

The question to be asked is this:  could a difference in the CRC screenings themselves be contributing to these disparities? New research shows the answer is yes.

Recent data published in the Journal of the National Cancer Institute demonstrate that the quality and full completion of a screening for colorectal cancer can have profound impacts on outcomes. In this first-of-its-kind modeling study, which was funded by Exact Sciences, my colleagues and I examined the impact of screening colonoscopy quality and completion of follow-up colonoscopy after a positive stool test on CRC incidence and mortality for Black adults. 

Studies show Black adults in the United States are more likely to receive a lower-quality screening colonoscopy than White adults^4-8. They are also less likely to complete a colonoscopy after a positive stool screening test for colon cancer (such as Cologuard or a FIT test)^9-16. Colonoscopy quality is assessed by “adenoma detection rate,” which measures the proportion of screening exams wherein the endoscopist finds a pre-cancerous lesion that can then be removed as a preventive step. Follow-up colonoscopy after a positive stool test is important because it’s needed to complete the screening process. These factors can contribute to disparities in outcomes because finding and removing pre-cancerous growths and early cancers is crucial to improving health outcomes from screening ^17-18. 

Our study modeled scenarios to look at how improving the quality of a screening colonoscopy (measured by adenoma detection rate) and completion of follow-up colonoscopy after a positive stool test would impact the rates at which Black adults get or die from colorectal cancer. We were surprised to find that eliminating difference in these two areas could cut the gap in CRC incidence and mortality between Black and White Americans in half. Together, eliminating the Black-White differences in colonoscopy quality and follow-up colonoscopy rates would eliminate 49% of the gap in CRC incidence and 59% of the difference in mortality, respectively.  This new evidence reveals two under-recognized areas where taking direct action can help lower incidence and mortality of CRC in Black adults. 

So, now what? We must continue to build on the progress of the last 10 years to get every eligible adult over age 45 screened for CRC.  But we must also ensure everyone gets a high-quality screening with the potential to identify and effectively treat pre-cancers and early-stage cancers. This study provides clear direction on two areas of focus that can make a meaningful difference: Detecting precancerous growths with the initial screening test and working to ensure people have access to high quality colonoscopies to complete screening if they start with a stool test and have a positive result. Improving these two areas won’t be easy. However, if we – healthcare providers, government, industry, advocacy, researchers, payers, and all committed stakeholders – make this a public health priority, we have a real chance to improve healthcare and CRC outcomes for Black adults.

Dr. Oguzhan Alagoz is the Procter & Gamble Bascom Professor in the Department of Industrial & Systems and Engineering and the Department of Population Health Sciences at the University of Wisconsin-Madison.

Sources:

1. National Cancer Institute. Surveillance, Epidemiology, and End Results http://seer.cancer.gov/.
2. Sabatino SA, Thompson TD, White MC, et al. Cancer Screening Test Use―US, 2019. American Journal of Preventive Medicine 2022;63(3):431-439.
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5. Fedewa SA, Flanders WD, Ward KC, et al. Racial and ethnic disparities in interval colorectal cancer incidence: a population-based cohort study. Annals of Internal Medicine 2017;166(12):857-866.
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14. Coronado GD, Dickerson JF, Burnett-Hartman AN, et al. Reduced Implementation and Completion of Average-Risk Annual Fecal Immunochemical Test Colorectal Cancer Screening in Black Patients Aged 45–49 Years. Clinical Gastroenterology and Hepatology 2022.
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