Even as racial disparities in screenings for colorectal cancer have narrowed, the discrepancies in outcomes between Black and white Americans remain stubbornly wide. Black adults are 23% more likely to be diagnosed with the disease and 31% more likely to die from it.
Madison, Wisconsin-based Exact Sciences, maker of one of the leading stool-based screenings for colorectal cancer, wanted to know why. So, the company turned to Oguzhan Alagoz, Procter & Gamble Bascom Professor of industrial and systems engineering at the University of Wisconsin-Madison and a renowned expert in using mathematical modeling to inform healthcare interventions and policy.
Alagoz, working with collaborators across the country and Exact Sciences’ in-house modeling team, found that eliminating differences between Black and white adults in two measures could significantly impact inequalities in disease outcome: the rate of follow-up colonoscopies after abnormal results from stool-based tests and adenoma detection rate among endoscopists who perform colonoscopies.
The team published its findings in a paper in the Journal of the National Cancer Institute in July 2024.
During a colonoscopy, a specialist examines the colon for precancerous polyps known as adenomas. Providers’ quality is measured by the rate at which they detect these polyps. Previous studies have shown Black adults receive screening colonoscopies that, on average, have a 10% lower rate of finding these polyps. In addition, Black adults lag by 15% in completion of a colonoscopy after an at-home, stool-based test, such as Exact Sciences’ Cologuard or a fecal immunochemical test (FIT), flags a patient as potentially having an issue.
When Alagoz and his collaborators simulated results with those two factors equalized using a mathematical model developed by Exact Sciences, they found that colorectal cancer incidence among Blacks would drop by 14.6% and deaths from the disease would decrease 18.7%.
“As long as you do not fix these gaps in quality and follow-up completions, even if you had similar screening rates, you are not going to solve these racial inequalities,” says Alagoz, who previously studied colorectal cancer but has primarily focused his attention on breast cancer over the past decade.
Still, while the results explain roughly half of the disparities in outcomes across racial lines, Alagoz says discrepancies remain.
“As a modeler, my next step is, how can I explain the remaining half?” he says. “I would like to work on that. To me, that’s a natural next step.”
This research was supported by Exact Sciences and the National Cancer Institute. UW-Madison alumna Travelle Franklin-Ford Ellis (PhDBME/MD ’13), health equity director at Exact Sciences, is among the authors of the paper.
Top photo by Jane Feller.