Stool-based CRC screening most effective, cheapest method in low-adherence settings
Key takeaways:
- Annual fecal immunochemical testing was the most effective and cheapest CRC screening method for underserved populations.
- Triennial blood testing was the least effective and most costly CRC screening method.
Among populations with low adherence to colorectal cancer screening, annual fecal immunochemical testing was the cheapest and most effective noninvasive screening method, according to a study published in JAMA Network Open.
Operating on limited resources, federally qualified health centers (FQHCs) rely upon noninvasive CRC screening tests — the most common of which is the annual fecal immunochemical test (FIT) — to treat underserved populations.
“The effectiveness and cost-effectiveness of noninvasive tests are not well studied in settings where adherence is low for both the noninvasive screening and follow-up colonoscopy,” Pedro Nascimento de Lima, PhD, associate engineer at RAND and professor of policy analysis at Pardee RAND Graduate School in Arlington, Virginia, and colleagues wrote.
This inspired the researchers to perform a simulation study to determine which screening method — including annual or biennial FIT, triennial multitarget stool DNA (mt-sDNA) test and triennial blood-based test — is the most effective and cost-effective in an FQHC setting with low adherence rates.
They used the CRC Simulated Population model for Incidence and Natural history to create a simulated cohort of 10 million individuals aged 50 years in 2025, representing a mostly Hispanic/Latino population served by a large FQHC system in Southern California.
The researchers projected outcomes through 2124.
The simulated population had a lower adherence to all steps of the screening process, including first-step noninvasive testing (45%), follow-up colonoscopy (40%) and ongoing surveillance (80%). Nascimento de Lima and colleagues found that all the screening scenarios reduced CRC cases and deaths and resulted in life-years gained (LYG). Additionally, perfect adherence increased the effectiveness of all scenarios.
In perfect and realistic screening scenarios, annual FIT was the most effective strategy, followed by triennial mt-sDNA testing, biennial FIT and triennial blood testing.
With realistic adherence, annual FIT yielded 121 LYG per 1,000 screened individuals, whereas triennial blood testing yielded 23 LYG per 1,000.
Further, the researchers found that all screening scenarios lowered treatment costs and yielded quality-adjusted LYG. However, only FIT-based screening plans yielded net cost savings, with a net monetary benefit of $5,883 per person with realistic adherence. In concordance with the results of the LYG analysis, triennial blood testing was linked to the greatest net costs and lowest net monetary benefit, at $3,485 per person with perfect adherence.
Notably, the researchers found that realistic adherence to annual FIT testing — based on 45% first-step adherence and 80% adherence to follow-up and colonoscopy — yielded more LYG than perfect adherence to triennial blood testing (88 vs. 77 LYG per 1,000).
The researchers noted several limitations to this study, including that they assumed a stagnant screening adherence over time rather than accounting for the potential increases when patients become eligible for Medicare.
“This study suggests that in a FQHC setting, prioritizing the convenience of blood tests over less costly and more effective existing stool-based tests could result in higher costs and worse population-level outcomes,” the authors wrote.
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