Advances in Faecal DNA Testing for Colorectal Cancer Screening: A Literature Review for Primary Care Providers

Abstract

Recent epidemiological data gathered by the Centers for Disease Control and Prevention (CDC) suggest that colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the USA. Clinicians currently use five types of test to screen for CRC. Two of these five types, the DNA stool test and the faecal occult blood test, are non-invasive. The DNA stool test successfully detects both advanced neoplasias and non-advanced adenomas with more sensitivity than the faecal occult blood test. However, data suggest that it also generates more false-positive results. There is only one DNA stool test that has been approved by the U.S. Food and Drug administration (FDA): the approved Cologuard® (Exact Sciences, Madison, Wisconsin, USA) test. This test screens for nine different DNA biomarkers, one haemoglobin biomarker, and one β-actin. This article is a literature review of research on faecal DNA biomarkers conducted in the past 5 years from four large databases. Key findings include the ability to reach a sensitivity as high as 98% to detect abnormalities in the colon using a multi-target stool DNA-based assay. In comparison, the Cologuard offers 92% sensitivity and 87% specificity for all stages of CRC. Testing DNA biomarkers can serve as an adequate screen for cancer and adenomas in average-risk adults. Areas for further research include implementing studies to compare long-term health consequences for patients who receive colonoscopies versus DNA stool tests, finding ways to improve both the sensitivity and specificity of screening tests, and finding ways to improve the detection of those biomarkers most associated with CRC, including microRNA detection in the marking panel.