Blood-Based Testing for Colorectal Cancer Screening is Not Quite Ready for Prime Time, Expert Says

Mark Fendrick, MD, professor of internal medicine at the University of Michigan School of Medicine and professor of health management and policy at the university's school of public health, fully supports innovation when it comes to advancing public health. In a recent interview with Patient Care, he revealed himself as the person "who coined the term 'the Katie Couric effect.'" Fendrick authored the analysis that showed the huge spike in colorectal cancer (CRC) screening following Couric's prime-time televised colonoscopy while she was a morning anchor on the Today Show.

In the rest of the conversation about the future for blood-based CRC screening, Fendrick, who is widely recognized for his research in the area of CRC screening and patterns of uptake, was clear that he doesn't believe the tests have reached the level of accuracy that would be required for widespread implementation. He expressed concern about the potential for many many false positives that would send people for follow-up colonoscopies--and the slots for those screenings are limited at best, Fendrick said.

He offers additional thoughts on balancing innovation with access in the video above.

The following transcript has been lightly edited for style and clarity.

Patient Care: How do you envision the future for blood-based screening for colorectal cancer?

Mark Fendrick, MD: I was the person who coined the term the Katie Couric effect and conducted the analysis that showed how Ms. Couric—who you may know, though some of your listeners might not—dramatically impacted colorectal cancer screening uptake when she underwent a colonoscopy live on the Today Show. It moved the needle in a way we’d never seen before.

We need to continue driving that kind of innovation—especially when it’s supported by rigorously studied interventions.

That said, I’m still not entirely convinced about the relative accuracy of blood-based tests compared to our current alternatives. Blood-based screening isn’t yet included in the U.S. Preventive Services Task Force (USPSTF) recommendations, which means it's not mandated to be covered at no cost to patients.

Still, having had two colonoscopies myself, I can acknowledge that a blood test is far more convenient—no prep, no time off work, no need for a driver. So while I would currently recommend stool DNA as my preferred non-invasive option, I recognize there are patients who refuse all other modalities. In those cases—and only in those cases—I’d consider recommending a blood-based test.

But that raises a new concern: what are we going to do with all the positive results? These tests will generate a high number of positives, and we must have a plan to manage them. As I said earlier, I’d much rather have a patient with a positive result—regardless of the modality—than a patient who was never screened at all.

That’s why, in my view, we need to be very intentional about how we allocate colonoscopy slots. I'm not a gastroenterologist, but it’s clear that we must prioritize these limited resources in a way that maximizes public health impact. And according to our modeling, that approach can also lead to better financial outcomes for the system overall.