The definition of a screening test is one that has a high sensitivity and specificity for diagnosing an easily-treatable precursor of cancer, with minimal side-effect spectrum. One should be detecting polyps, not cancers. All stool/blood tests are only providing a possible lead-time bias; they do not compromise e screening. There is a combination of CT Colonography with colonoscopy+/- flexible sigmoidoscopy that can provide the right balance when worked out by medics and population statisticians
Stool-DNA-Based Screening More Sensitive Than FIT for Colorectal Cancer — Physician’s First Watch
Stool-DNA-Based Screening More Sensitive Than FIT for Colorectal Cancer
By Joe Elia
A colorectal cancer screening test that measures DNA biomarkers of the disease in stool showed greater sensitivity but lower specificity than fecal immunochemical testing (FIT), according to a New England Journal of Medicine study.
Researchers, including employees of the company developing the test, examined results in some 10,000 patients at average risk for colorectal cancer. All underwent colonoscopy as well as DNA and FIT testing. With colonoscopy as the standard, DNA testing was significantly more sensitive than FIT at detecting colorectal cancer (92% vs. 74%), but it had lower specificity (87% vs. 95%).
Editorialists note the high technical and logistical failure rate with DNA testing, which led to twice as many subjects being excluded from analysis as those who were excluded because of colonoscopy failures.. They point to the need for comparative-effectiveness studies to clarify DNA testing's role in screening.