Written by Peter Liu
Spoon Feed
Multitarget stool DNA (mt-sDNA) tests detect more colorectal cancer (CRC) than standard fecal immunochemical (FIT) tests.
Stool DNA catches more than FIT
We previously discussed fitting the FIT to the sitch. To summarize:
- Several FIT tests are available to screen for CRC, and the performance of each test varies significantly.
- Standard FIT tests are antibody tests to detect hemoglobin and are usually performed annually. Multitarget stool DNA tests (mt-sDNA) can be added to FIT testing (e. g. Cologuard) to increase testing sensitivity and allow for less frequent testing (e. g. every 3 years) but have lower specificity for colorectal cancer. There are now investigational “next-generation” mt-sDNA tests designed to have better performance than Cologuard, but they are not available on the market yet
- There are quantitative and qualitative tests available.
We have previously suggested that, where many test options are available, it would be reasonable to choose high-specificity tests for patients that are treatment-averse, and high-sensitivity tests for those that prefer the peace of mind of “not missing something.”
Today’s featured meta-analysis compares the performance of mt-sDNA and FIT tests, systematically reviewing 55 studies (n=450,979) that evaluated mt-sDNA or FIT performance using colonoscopy as the reference. Of note, the 14 studies that evaluated mt-sDNA testing included 2 studies that assessed next-generation mt-sDNA testing. Overall, mt-sDNA testing showed higher sensitivity (93.2%; 95%CI 89.0–95.8) vs. FIT (71.6%; 64.3–77.9) for detecting colorectal cancer; specificity was slightly lower (91.6% vs. 96.3%). mt-sDNA also outperformed FIT for advanced precancerous lesion detection (sensitivity 43.5% vs. 22.2%).
This studies included had significant heterogeneity, and there is nuance in stool testing and the patients using them. However, this affirms the general consensus that mt-sDNA testing is the more sensitive test for CRC screening.
How does this change my practice?
In most practices, practical factors often determine FIT test choices. For example, in my practice setting, the lab can hand out standard FIT tests to patients to take home and use immediately, whereas Cologuard orders have to be faxed. However, some patients strongly favor the 3-year testing frequency of Cologuard over the 1-year frequency of FIT. I find these factors often determine test choices. However, where applicable, I prefer quantitative FIT tests over qualitative tests, and I prefer mt-sDNA testing over standard FIT tests, except in rare situations where maximizing specificity makes sense (e.g. interest in cancer screening, but general treatment-aversion).
Source
Multi-target stool DNA and the Fecal Immunochemical Test: A Systematic Review and Meta-analysis on Test Performances. Am J Prev Med. 2025 May 14:107654. doi: 10.1016/j.amepre.2025.107654. Epub ahead of print. PMID: 40379061
