From the Guidelines
The most effective stool test for detecting colon cancer is the multitarget stool DNA test (Cologuard), which has been shown to be more sensitive than the fecal immunochemical test (FIT) for detecting colorectal cancer and advanced precancerous lesions. This is based on a study of 9,989 participants at average risk for CRC, which found that the mt-sDNA test was more sensitive than FIT for detecting CRC (92.3% vs 73.8%; P=.002) 1. The mt-sDNA test screens for the presence of known DNA alterations (KRAS mutations, aberrant NDRG4 and BMP3 methylation) during colorectal carcinogenesis in tumor cells sloughed into stool, as well as occult blood as measured by immunoassay. Some key points to consider when using the mt-sDNA test include:
- It has a higher sensitivity than FIT for detecting CRC and advanced precancerous lesions 1
- It has a lower specificity than FIT, which may result in more false positives 1
- It is typically done every three years, whereas FIT is recommended annually
- Any positive result from the mt-sDNA test requires follow-up with a colonoscopy for confirmation and potential treatment. The mt-sDNA test is a useful option for CRC screening, particularly for individuals who are at average risk for CRC and prefer a non-invasive test 1.
From the Research
Colon Cancer Detection using Stool Tests
- The Fecal Immunochemical Test (FIT) is a screening test that detects human hemoglobin in the stool, making it a common method for colon cancer detection 2, 3, 4.
- FIT has been shown to increase screening uptake and improve colon cancer outcomes, with its use being the most common colon cancer screening modality worldwide and second most common in the United States 2.
- Studies have compared the efficacy and cost-effectiveness of FIT versus colonoscopy in colon cancer screening, with results indicating that FIT may be similar to one-time colonoscopy in detecting colon cancer, although it has lower detection rates of any adenoma and advanced adenoma than one-time colonoscopy 3.
- A new-generation FIT has been found to be superior to guaiac-based tests in detecting colon cancer among colonoscopy referral patients, with higher sensitivity and specificity 5.
- The choice between colonoscopy and FIT as the screening tool of first choice is still debated, with ongoing comparative effectiveness trials and health economics analyses aiming to provide further context on the relative advantages of these tests 6.