Annual Stool-Based CRC Screening Shows Greatest Benefit for Low Adherence Populations

Carolyn Rutter, PhD

Credit: Fred Hutch Cancer Center

Annual colorectal cancer (CRC) screening with fecal immunochemical testing (FIT) is the most effective and least costly strategy in patient populations where screening adherence is low, according to findings from a recent study.¹

Using the validated Colorectal Cancer Simulated Population model for Incidence and Natural history (CRC-SPIN) microsimulation model, investigators projected screening outcomes for a cohort of 10 million individuals and found annual screening with FIT was the most cost-effective strategy, while triennial blood-based screening was the least effective and most costly strategy.¹

While colonoscopy is widely regarded as the “gold standard” for CRC screening, noninvasive tests have gained traction in recent years to help improve screening rates among patients who are unable to or do not wish to receive a colonoscopy. In 2024, the US Food and Drug Administration approved 3 new noninvasive CRC tests, including ColoSense, a multi-target stool RNA (mt-sRNA) test; Shield, the first-ever blood test for primary CRC screening; and Cologuard Plus, a next-generation multitarget stool DNA test.²

“Previous modeling studies found that blood-based test screening would not be effective when population-level screening rates reflect national levels,” Carolyn Rutter, PhD, a professor with the Hutchinson Institute for Cancer Outcomes Research and the Biostatistics Program within the Public Health Sciences Division at Fred Hutch Cancer Center, and colleagues wrote.¹ “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.”

To address this gap in research, investigators assessed the cost-effectiveness and outcomes associated with noninvasive CRC screening strategies, including new blood-based tests, in a Federally Qualified Health Center (FQHC) setting with low adherence rates using a recalibrated version of CRC-SPIN designed to predict the 2017-2021 CRC incidence for Hispanic adults aged 45 to 49 years in the Los Angeles Surveillance, Epidemiology, and End Results Registry.¹

Investigators simulated 4 screening strategies: no screening; annual FIT; biennial FIT; triennial mt-sDNA test; and a triennial blood test (Shield; Guardant Health). The analyses focused on 2 primary screening adherence scenarios: perfect adherence (100%), which was used as a reference, and realistic adherence (45%) to a noninvasive screening test that reflected pre-COVID-19 pandemic screening levels observed in FQHCs.¹

Outcomes of interest included CRC incidence and mortality; life-years gained and quality-adjusted life-years (QALYs) gained relative to no screening; costs; and net monetary benefit (NMB) assuming a willingness to pay of $100 000 per quality-adjusted life-year gained.¹

Without screening, the projected amount of lifetime CRC cases in the target population was 66.0 per 1000 individuals, leading to 27.3 CRC deaths.¹

Investigators noted realistic adherence to annual FIT screening with 80% adherence to follow-up colonoscopy was more effective than a triennial blood test with perfect adherence, yielding fewer CRC cases (32.0 vs 37.7) and CRC deaths per 1000 individuals (11.3 vs 13.0) as well as more life-years gained per 1000 individuals (183 vs 167) while requiring fewer follow-up and surveillance colonoscopies per 1000 individuals (816 vs 1144).¹

Without screening, the lifetime mean projected cost of CRC care, entirely attributable to diagnosis and treatment, was $4873 per person. While every screening scenario reduced treatment costs and yielded QALY gains, only FIT-based screening yielded net cost savings.¹

Specifically, findings showed annual FIT resulted in the most QALYs gained, followed by triennial mt-SDNA tests and biennial FIT, whereas triennial blood tests yielded the least QALYs gained. Annual FIT testing also yielded the largest cost savings and highest NMB, indicating the greatest value across all tests examined.¹

Of note, the NMB of annual FIT with realistic adherence was greater than the NMB of a triennial blood test with perfect adherence ($5883 vs $3485 per person). Further analysis revealed the NMB of annual FIT with realistic screening adherence and 80% follow-up colonoscopy adherence was $9476. Compared with a blood test with perfect adherence, this strategy was projected to result in 11 QALYs gained per 1000 and $4902 lifetime net cost savings per person.¹

“Setting health policy based on increasing adherence to noninvasive screening, without considering effectiveness and adherence to follow-up colonoscopy, could waste health care resources and result in inferior patient outcomes,” investigators wrote.¹ “The additional resources needed to pay for blood tests could otherwise be used to improve population-level health, including navigation for patients with abnormal FIT results to improve receipt of follow-up colonoscopy.”

References

1. ^{Nascimento de Lima P, Matrajt L, Coronado G, et al. Cost-Effectiveness of Noninvasive Colorectal Cancer Screening in Community Clinics. JAMA Network Open. doi:10.1001/jamanetworkopen.2024.54938}
2. ^{Brooks A. Gastroenterology Year in Review: 2024. HCPLive. December 29, 2024. Accessed January 15, 2025. https://www.hcplive.com/view/gastroenterology-year-in-review-2024}