Real-world multi-target stool DNA longitudinal adherence for colorectal cancer re-screening in a large, national population.
Authors: Greene Mallik , Dore Michael , Ebner Derek W. , Pew Timo , Johnson William , Kisiel John B. , Fendrick A. Mark , Ozbay Burak Burak , Limburg Paul J. 
Published: June 2024

e15633 Background: Colorectal cancer (CRC) is the fourth most diagnosed cancer, as well as the second leading cause of cancer death in the United States – with an estimated 152,810 diagnoses and 53,010 fatal cases in 2024. Regular screening and early detection can reduce CRC incidence and improve overall survival; however, recent national survey data (2021) demonstrate that only 59% of the US screen-eligible population (≥ age 45) is up to date. Home-based, non-invasive CRC screening test options, such as the multi-target stool DNA (mt-sDNA) test, have the potential to improve patient outcomes and overcome CRC screening adherence barriers at multiple levels. Given that the recommended interval for mt-sDNA is three years, a better understanding of use in repeat users is warranted. We evaluated the effective rescreen rate of previous mt-sDNA test users. Methods: In this retrospective cohort study, we included patients between the ages of 45 and 75 years who were shipped an mt-sDNA test kit between January 1st – December 31st, 2023, and had previously completed mt-sDNA screening with a negative result > 2.5 years prior. Our primary variable of interest was mt-sDNA completion rate on repeat testing, defined as kit receipt with a valid result within 120 days of the shipment date. Regression analysis was performed to determine baseline characteristics associated with repeat test completion rate. Results: During the analysis period, a total of 481,748 patients who met the inclusion criteria received an mt-sDNA kit. The majority of the cohort was female (61.4%) and between the ages of 65-75 years (50.9%). Overall repeat test completion rate was 83.6%, with the average time to kit return being 18.9 days. Completion rates were similar between males (83.8%) and females (83.6%), and patients receiving included navigation support via mobile phones demonstrated the shortest average time to kit return (18.7 days). Completion rates increased concordantly with patient age: 81.6%, (45-49 years), 82.2% (50-64 years), and 85% (65-75 years). For first-time rescreen participants (2nd lifetime mt-sDNA test), the completion rate was 83.1%. For second-time rescreen participants (3rd lifetime mt-sDNA test), the completion rate was even higher at 93.6%. Logistic regression analyses revealed that patients re-screening for a second-time were three times more likely to return the mt-sDNA kit for CRC screening (OR = 3.118; p < 0.001). Conclusions: Data from this large, retrospective cohort study revealed that repeat CRC screening with the mt-sDNA test is associated with high adherence to triennial follow-up among participants. suggesting a high-level of perceived patient confidence in repeat performance of the mt-sDNA test. These novel data provide relevant insights regarding strong patient willingness to continue with home-based, non-invasive mt-sDNA testing over multiple cycles of average-risk CRC screening.