P0354 - Critical Adherence to Blood-Based vs Stool-Based Screening for Colorectal Cancer: A Scenario Analysis

Reinier Meester, MS, PhD¹, Andrew Piscitello, MSEd², Lance Baldo, MD³, Peter S. Liang, MD, MPH^4
1Freenome Holdings, Inc., South San Francisco, CA; ²EmpiriQA LLC, Long Grove, IL; ³Freenome, Inc., South San Francisco, CA; ⁴NYU Grossman School of Medicine, New York, NY

Introduction: Blood tests are among the latest innovations in colorectal cancer (CRC) screening. Large, representative, prospective studies with colonoscopy as a reference standard provide diagnostic performance estimates of these non-invasive tests. Data suggest that blood test sensitivity may be higher for CRC but lower for advanced adenomas (AA) compared to some stool tests, and that blood tests are more acceptable to patients. We investigate how these differences impact long-term outcomes of blood-based vs. stool-based screening and identify critical adherence thresholds for similar patient benefit.

Methods: A Cancer Intervention and Surveillance Modeling Network (CISNET) model was replicated to compare screening from age 45 to 75 years, using annual FIT (AA sensitivity, CRC sensitivity, specificity: 24%, 74%, 96%), FIT-DNA every 3 years (42%, 92%, 90%), or 2 alternative blood tests every 3 years: a low-sensitivity blood test (lsBT) satisfying minimum U.S. coverage criteria (10%, 74%, 90%), and an evidence-informed test with higher sensitivity (hsBT) for adenomas and cancer (20%, 90%, 90%). Uptake assumptions were varied to explore changes in lifetime benefit of screening, as measured by CRC cases averted, CRC deaths averted, and life-years gained (LYG).

Results: Among 1000 unscreened U.S. adults, there were an estimated 70.7 lifetime CRC cases and 27.1 CRC deaths. Screening with 100% adherence reduced incidence by 30.3–53.3 cases (43–75%), reduced mortality by 13.6–21.7 deaths (50–80%) (Table) and yielded 158.2–252.5 LYG. FIT was the most efficacious, followed by FIT-DNA, hsBT, and then lsBT. With different levels of relative adherence, hsBT would yield greater LYG than FIT-DNA when adherence to FIT-DNA was < 84.3% relative to hsBT; LYG was greater for hsBT than FIT when adherence to FIT was < 75.9% relative to hsBT (Figure). lsBT would yield greater LYG than the stool-based tests when adherence to FIT-DNA was < 69.6% and adherence to FIT was < 62.7% relative to lsBT (Figure).

Discussion: As a novel noninvasive CRC screening modality, blood tests have potential to improve CRC screening outcomes, especially when patients prefer the modality over existing tests. This finding confirms the adage that ‘the best test is the one that gets done.’




Disclosures:


Reinier Meester, MS, PhD¹, Andrew Piscitello, MSEd², Lance Baldo, MD³, Peter S. Liang, MD, MPH⁴. P0354 - Critical Adherence to Blood-Based vs Stool-Based Screening for Colorectal Cancer: A Scenario Analysis, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.