
Key Takeaways:
A recent study published in JAMA Network Open suggests that blood-based colorectal cancer (CRC) screening tests are less effective and more costly than stool-based methods.
The study analyzed real-world adherence rates in federally qualified healthcare settings, focusing on underserved populations.
Fecal tests (FIT and stool DNA tests) emerged as the most effective and cost-efficient screening strategies, delivering more life years gained per person than blood tests.
Blood-based CRC screening, despite recent FDA approval, was the least effective strategy, yielding significantly fewer life years gained and negative net monetary benefits.
Study Overview: Blood-Based vs. Stool-Based Colorectal Cancer Screening
Colorectal cancer remains one of the leading causes of cancer-related deaths worldwide, making effective screening methods essential for early detection and improved patient outcomes. A recent study, published in JAMA Network Open and reported by The American Journal of Managed Care, analyzed the cost-effectiveness and patient outcomes of different CRC screening methods, with a particular focus on blood-based tests versus traditional stool-based screenings.
The study was conducted in federally qualified healthcare settings, where adherence to screening recommendations can be inconsistent. The goal was to evaluate whether blood-based CRC tests could be a viable alternative to stool-based screenings, especially in populations with historically low compliance rates.
Key Findings: Why Blood-Based Tests Fall Short
1. Adherence Challenges in CRC Screening
Screening effectiveness is directly linked to patient adherence—meaning how well patients follow through with the recommended steps in a multi-stage screening process. The study focused on a predominantly Hispanic or Latino cohort and revealed low adherence rates at multiple screening steps, which significantly impact the overall effectiveness of any CRC screening strategy:
First-step noninvasive testing (fecal or blood-based test): 45% adherence
Follow-up colonoscopy after an abnormal noninvasive result: 40% adherence
Surveillance colonoscopy for high-risk findings: 80% adherence
This drop-off in adherence, particularly at the follow-up colonoscopy stage, is a major concern. Without completing all necessary screening steps, the benefits of any test—whether blood-based or stool-based—are significantly reduced.
2. Fecal-Based Tests Are More Effective and Cost-Efficient
Among the screening methods analyzed, stool-based tests (FIT and stool DNA tests) proved to be the most effective and cost-efficient option:
121 life years gained per 1,000 screened individuals
A net monetary benefit of $5,883 per person
These findings reinforce that fecal-based testing remains the best noninvasive screening method for detecting CRC early while maintaining cost efficiency.
3. Blood-Based Screening: The Least Effective and Most Expensive Strategy
Despite the FDA’s recent approval of blood-based CRC tests, the study found them to be the least effective screening method:
Only 23 life years gained per 1,000 screened individuals
A negative net monetary benefit, meaning they introduce more costs to the healthcare system while providing fewer health benefits
These results suggest that while blood-based screening may be an appealing option for patients who avoid traditional CRC tests, it does not offer the same life-saving potential as stool-based tests or colonoscopy.
FDA Approval of Blood-Based CRC Tests: A Double-Edged Sword?
In an effort to increase screening participation, the FDA recently approved a blood-based CRC screening test, positioning it as an alternative for individuals who might otherwise forgo screening altogether. While the intention is to provide a less invasive option, the findings from this study indicate that replacing established stool-based CRC screenings with blood tests could lead to increased CRC incidence and mortality.
Blood-based tests rely on detecting circulating tumor DNA (ctDNA), which may not appear in the bloodstream during early stages of colorectal cancer. This means many cases could go undetected until the disease has progressed, significantly reducing the chance of successful treatment.
What This Means for Patients and Healthcare Providers
1. Fecal Tests and Colonoscopy Should Remain the Primary CRC Screening Methods
FIT and stool DNA tests are the most cost-effective and clinically beneficial noninvasive screening tools available today.
Colonoscopy remains the gold standard for detecting and preventing CRC by removing precancerous polyps before they develop into cancer.
2. Blood-Based Tests Should Be Used as a Last Resort
For patients unwilling to complete stool-based tests or a colonoscopy, blood-based screening may serve as an alternative.
However, relying solely on blood tests is not advisable, as they provide significantly fewer life years gained and are associated with higher costs.
3. Increasing Adherence is Key to Better Outcomes
Improving patient education about the importance of follow-up colonoscopy after an abnormal noninvasive test is crucial.
Expanding access to stool-based tests and reducing barriers to colonoscopy (such as cost and availability) should remain a priority for healthcare providers.
Conclusion: A Cautionary Approach to Blood-Based CRC Screening
While the development of blood-based colorectal cancer screening tests is an exciting advancement in medical technology, the data does not yet support replacing stool-based tests or colonoscopy as the primary screening tools.
The findings from this study clearly show that blood-based tests provide fewer life-saving benefits and come at a significantly higher cost. For healthcare providers and policymakers, the focus should be on improving adherence to existing, proven screening methods rather than shifting toward less effective alternatives.
Final Takeaway:
✅ For the best patient outcomes, stool-based tests and colonoscopies should remain the preferred screening strategies.
❌ Blood-based screening should only be used in select cases where other methods are not feasible.
As colorectal cancer screening continues to evolve, it is crucial that decisions are guided by evidence-based research to ensure the best possible care for patients.