As non-invasive colorectal cancer screening expands, the harder question may be what happens after a positive result.
“The value of screening isn't simply finding a signal. It's making sure that signal leads somewhere.”
Colorectal cancer screening is entering a remarkable period. In roughly two years, four non-invasive screening tests have received FDA approval. Blood-based screening has entered clinical practice. The American Cancer Society's 2026 guideline now formally recognizes blood-based testing as an option for some patients. And investment in the category suggests that this is only the beginning of a much broader expansion in how, and where, people are screened.
For a field that has spent decades trying to reach patients unwilling or unable to undergo colonoscopy, this is meaningful progress. Screening is becoming easier to access, easier to offer, and increasingly compatible with the way patients actually live.
That deserves to be celebrated. But it also raises a question that becomes more important with every new screening option we introduce: What happens after a test comes back positive? Because a positive screening result is not an outcome. It is the beginning of a clinical journey.
Detection and prevention are not the same thing
One of the great advantages of colonoscopy is that detection and intervention can occur during the same procedure. A physician can identify a precancerous lesion and remove it before it develops further.
Non-invasive screening works differently. Whether the initial signal comes from stool or blood, an abnormal result requires another step. The patient must understand what the result means, connect with the appropriate provider, schedule a colonoscopy, prepare for the procedure, and ultimately complete it.
Until that happens, the screening journey remains unfinished. This distinction matters because the growth of non-invasive screening changes more than the way patients enter the system. It also increases the importance of everything the system must do afterward.
The easier we make it to generate a screening signal, the more important it becomes to make sure we can resolve it.
Where patients are still being lost
Unfortunately, that transition remains one of the weakest points in colorectal cancer screening. A 2023 analysis across 39 healthcare organizations found that only 53.4% of patients completed a follow-up colonoscopy after a positive stool-based test. Other analyses suggest that 30% to 40% of patients with a positive non-invasive result may never complete the diagnostic colonoscopy that should follow.
Those aren't simply missed appointments. They represent patients for whom screening successfully identified risk but the healthcare system did not complete the journey.
And the consequences are measurable. The research cited in our companion paper associates failure to complete follow-up with approximately 1.8 times the risk of colorectal cancer death over the following six years.
This is where our definition of screening success may need to evolve. Historically, much of the conversation has centered on participation: Did the patient get screened? Increasingly, we may need to ask a second question: Did the patient reach resolution?
A different way to think about capacity
The expansion of non-invasive screening sometimes raises another concern. If more patients screen outside the endoscopy suite, will the healthcare system have enough colonoscopy capacity to evaluate all of the positive results that follow?
Recent modeling suggests the more interesting issue may not be the total number of colonoscopies available, but how we use them. Research cited in the companion paper estimates that the United States performs roughly 15 million colonoscopies annually. About one-third are currently used for primary screening in average-risk populations, while a much smaller share is devoted to following up positive non-invasive tests. Modeling suggests that shifting more of that existing capacity toward higher-yield diagnostic follow-up could substantially improve cancer detection and prevention without increasing the total number of procedures performed.
That suggests an interesting possibility. Non-invasive screening and colonoscopy may not be competing approaches at all. They may increasingly become parts of the same system: one expanding access and identifying risk, the other providing diagnostic resolution and, when appropriate, prevention.
If so, the challenge isn't choosing between them. It's connecting them.
The infrastructure between the moments
Healthcare tends to organize itself around events. A test is ordered. A result is returned. A referral is made. A procedure is scheduled.
Patients experience something different. They experience the spaces between those events. The phone call that never comes, the referral they don't understand, the appointment they can't schedule, the result that sits in one system while the next provider works in another.
Those spaces rarely receive the same attention as the technologies on either side of them. Yet they may ultimately determine whether innovation improves an outcome.
There is encouraging evidence that those gaps are not inevitable. Organized programs that combine screening with systematic outreach, navigation, reminders, and streamlined follow-up have demonstrated dramatically higher participation and better outcomes. Kaiser Permanente Northern California's experience is particularly instructive: over time, a coordinated FIT screening program accompanied by structured follow-up was associated with screening adherence approaching 80%, substantial reductions in colorectal cancer incidence and mortality, and narrower racial disparities.
The lesson isn't that one particular model should be replicated everywhere. It's that implementation matters. A screening technology can create an opportunity. The surrounding system determines whether healthcare captures it.
What wider access requires next
As screening becomes more distributed, healthcare will need better ways to connect what happens between an abnormal result and a completed diagnosis. Laboratories, primary care practices, specialists, health plans, and patients all participate in that journey, but no single organization owns it from beginning to end.
At Aton Health, we’ve begun to think of the growing ecosystem around that challenge as the resolution marketplace: the clinical, operational, and economic activity required to carry a screening signal through to diagnostic resolution.
It isn’t a new category of test or a single technology platform. It is the increasingly important space between detection and completed care. And as screening becomes easier to access, that space may become one of the most consequential parts of the system.
A Question Worth Asking: As we make cancer screening easier to access, are we investing equally in the systems required to ensure that every positive result reaches clinical resolution?
Go Deeper
Explore the research and evidence behind this essay in our companion white paper, The Resolution Marketplace.
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About the Author:
Tom Sanders is CEO and co-founder of Aton Health. Through this ongoing essay series, he explores the systems, operational realities, and clinical pathways that determine how healthcare innovation becomes better patient care.