Clinical Utility of a Blood-based Protein Assay on Diagnostic Colonoscopy Referrals for Elevated-risk Colorectal Cancer Patients in Primary Care

Background: Colonoscopies are effective in finding early stage colorectal cancer (CRC), which when found in a timely manner, dramatically improve survival rates. A significant number of at-risk patients are still not screened. We investigated the utility of a blood-based protein assay to assess for CRC in patients with elevated risk on the quality of preventive care delivered by board-certified primary care physicians (PCPs) in the United States. Methods: We report on the results of a 3-part, longitudinal, randomized controlled trial. Part 1 assessed physicians' ability to identify simulated patients at risk for CRC and found PCPs missed colonoscopy referrals for high-risk patients similar to 40% of the time. Part 2 randomized PCPs into control and intervention arms and demonstrated that a novel blood-based protein assay increased referral rates for a diagnostic colonoscopy when caring for simulated patients. Part 3, reported herein, compares real-world colonoscopy rates of actual patients cared for by control versus intervention physicians. Part 3 was executed to confirm whether the use of the assay demonstrated the same utility in their real world, high-risk patients as found in part 2 using simulated patients. Results: In the simulations, physicians with access to the assay were significantly more likely to order diagnostic colonoscopies. Similarly, in real-world practice, patients were also more likely to be referred for a diagnostic colonoscopy (odds ratio, 4.57; 95% confidence interval, 1.19-17.57). Conclusions: An increase in CRC risk, as indicated by the assay in simulated and real-life patients, was associated with a higher likelihood of appropriate patients being referred to diagnostic colonoscopy.