The Utility of Multitarget Stool DNA Testing in Community-Based Clinical Practice

Area of Science:

• Oncology
• Gastroenterology
• Preventive Medicine

Background:

• Multitarget stool DNA (MT-sDNA) tests, such as Cologuard, are recommended for colorectal cancer (CRC) screening.
• The US Preventive Services Task Force suggests screening every 1-3 years.
• This study evaluated MT-sDNA test performance and subsequent colonoscopy findings in a primary care setting.

Purpose of the Study:

• To assess the diagnostic performance of MT-sDNA testing for colorectal cancer (CRC).
• To analyze colonoscopy findings following a positive MT-sDNA test result.
• To evaluate the effectiveness of MT-sDNA screening in an average-risk population.

Main Methods:

• Retrospective cohort study using electronic health records from 35 primary care facilities (Winter 2019-Spring 2023).
• Included patients who underwent MT-sDNA testing, excluding high-risk individuals or those with prior negative tests/colonoscopies.
• Pathology assessment included CRC and advanced adenomas.

Main Results:

• Of 3,119 patients who completed MT-sDNA tests, 482 (15%) were positive.
• Follow-up colonoscopies in 253 patients revealed 10 (4%) with CRC and 61 (24%) with advanced adenomas.
• A significant majority (73%) of positive MT-sDNA tests did not lead to a diagnosis of CRC or advanced adenomas.

Conclusions:

• The observed CRC detection rate (0.2%-0.3%) was lower than anticipated for a screening cohort.
• A high false-positive rate (73%) for advanced adenomas or CRC was observed among patients with positive MT-sDNA tests.
• Findings suggest a need to re-evaluate the effectiveness of MT-sDNA screening in average-risk populations.