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

Peabody, John MD, PhD, DTM&H*,†,‡; Rahim, Arshad MD§; Wilcox, Bruce PhD; McGehee, Carrie ADN; Estigarribia, Erwin BE; Paculdo, David MPH; Arzadon, Aislinn MD; Fugaro, Steven MD*; Tran, Mary MS; Spitzer, Gary MD#

American Journal of Clinical Oncology: September 2019 - Volume 42 - Issue 9 - p 687–691
doi: 10.1097/COC.0000000000000578
Original Articles: Gastrointestinal

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 ~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.

*University of California, College of Medicine, San Francisco

QURE Healthcare, San Francisco

University of California, Fielding School of Public Health, Los Angeles

Applied Proteomics, San Diego, CA

§ARK Group, New York, NY

St. Luke’s Medical Center, Global City, Taguig, Philippines

#Strategic Medical Testing Services, Columbia, SC

Supported by Applied Proteomics Inc., San Diego, CA.

QURE, LLC, whose intellectual property was used to prepare the cases and collect the data, was contracted by Applied Proteomics Inc.

Reprints: John Peabody, MD, PhD, DTM&H, 450 Pacific Avenue, Suite 200, San Francisco, CA 94133. E-mail:

Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.