P2670 - Real-World Follow-Up and Outcomes After Positive Multitarget Stool DNA Testing: A National Analysis of Diagnostic Yield, Timing, and Resource Utilization

Mohammad Abuassi, MD¹, Jason John, MD², Kinan Obeidat, MD³, Sahithi Burra, MD⁴, Bahar Rehan, MD¹, Seela Ramesh, MD⁵, Lynna Alnimer, MD⁶
1University of Central Florida, HCA Healthcare GME, Gainesville, FL; 2University of Central Florida, HCA Healthcare GME, Orlando, FL; 3University of Texas Medical Branch, Santa Fe, TX; 4University of Central Florida, Orlando, FL; 5University of Central Florida College of Medicine, Orlando, FL; 6Henry Ford Health, Novi, MI

Introduction: Multitarget stool DNA (mt-sDNA) testing is a widely used noninvasive colorectal cancer (CRC) screening tool. However, real-world data on downstream diagnostic colonoscopy timing, clinical outcomes, and healthcare utilization remain limited. This study aims to evaluate post-test follow-up patterns, diagnostic yield, and procedural utilization in a large national cohort, including a focused analysis of false-positive cases.

Methods: We conducted a retrospective cohort study using the TriNetX network, a de-identified, federated health research platform comprising electronic health records from 66 healthcare organizations. Adults aged ≥45 years with a positive mt-sDNA test result between 2015 and 2025 were identified. Time-to-event analysis measured the interval from test to colonoscopy, with censoring at the time of colonoscopy or at 1,086 days. Outcomes included CRC, adenomas, diverticulosis, colectomy, diagnostic imaging and 1-year mortality. A nested analysis was performed to evaluate patients with false-positive mt-sDNA results, defined with no CRC or benign colorectal neoplasms on colonoscopy, with 10 years follow-up.

Results: Among 13,364 adults with a positive mt-sDNA test, the mean age was 65 (±10) years, and 53.5% were female. The majority were White (87.8%), with 7.1% Black and 3.0% Hispanic representation. The median time to colonoscopy was 69 days (IQR: 38–142), with 25% waiting over 3 months. Among those who completed colonoscopy, 2.5% (n = 332) were diagnosed with CRC, 19.1% (n = 2,550) had adenomas, and 6.6% (n = 883) had diverticulosis. Colectomy was performed in 1.5% (n = 199), and all-cause mortality remained < 0.1%. Imaging utilization included CT abdomen/pelvis (8.5%), abdominal ultrasound (4.5%), and nuclear medicine scans (4.8%).
In the subset of 5,277 patients with false-positive mt-sDNA results, the mean time to the next colonoscopy was 937 days (±642), with a median of 976 days (range: 30–3,484 days). 6.7% were later diagnosed with adenomas, 0.19% with CRC.

Discussion: In this national analysis, mt-sDNA led to clinically significant diagnostic yield in patients completing colonoscopy. However, a significant proportion of follow-ups revealed no pathology, yet incurred further testing and procedures. These findings highlight opportunities to improve risk stratification and post-test care pathways through more efficient and coordinated follow-up, particularly in false-positive cases, to maximize noninvasive screening value and optimize resource utilization and costs.


Figure: The left panel shows a histogram depicting the distribution of time (in days) to colonoscopy among patients with a positive mt-sDNA test. A large proportion underwent follow-up within 30–90 days, though notable delays were observed. In contrast, the right panel presents the distribution of time (in months) to colonoscopy for patients with false-positive mt-sDNA results.


Figure: This bar chart illustrates the percentage of patients who experienced various clinical outcomes or underwent diagnostic imaging within one year of a positive multitarget stool DNA (mt-sDNA) test.

Disclosures:
Mohammad Abuassi indicated no relevant financial relationships.
Jason John indicated no relevant financial relationships.
Kinan Obeidat indicated no relevant financial relationships.
Sahithi Burra indicated no relevant financial relationships.
Bahar Rehan indicated no relevant financial relationships.
Seela Ramesh indicated no relevant financial relationships.
Lynna Alnimer indicated no relevant financial relationships.

Mohammad Abuassi, MD¹, Jason John, MD², Kinan Obeidat, MD³, Sahithi Burra, MD⁴, Bahar Rehan, MD¹, Seela Ramesh, MD⁵, Lynna Alnimer, MD⁶. P2670 - Real-World Follow-Up and Outcomes After Positive Multitarget Stool DNA Testing: A National Analysis of Diagnostic Yield, Timing, and Resource Utilization, ACG 2025 Annual Scientific Meeting Abstracts. Phoenix, AZ: American College of Gastroenterology.