Colorectal Cancer Screening: Stool DNA and Other Noninvasive Modalities

tions.In this review we discuss stool DNA and other commercially available noninvasive colorectal cancer screening modalities in addition to other targets which previously have been or are currently under study.(Gut Liver 2016;10:204-211) Key Words: Colorectal cancer; Colorectal cancer screening; sDNA; Stool DNA 49,700 die annually, 3 suggesting the need for continued screening efforts.The basis of CRC screening dates to the discovery of precancerous adenomatous tissue, 4 which led to the understanding of development of CRC through the "adenoma-carcinoma" sequence rather than directly arising from the colorectal mucosa.5,6 Screening allows for early detection of CRC and removal of precancerous lesions, leading to reductions in cancer incidence and mortality.7,8 Despite strong evidence for CRC screening, 9 adherence to screening in the United States remains a challenge as only 65% of the eligible U.S. population is up-to-date with screening, while nearly 28% has never been screened.10 Challenges in increasing adherence have been attributed to patient and provider preferences, available resources, and healthcare infrastructure.11 Guidelines from several professional organizations, including the U.S. Preventive Services Task Force, Multi-Society Task Force, American College of Gastroenterology, and the National Comprehensive Cancer Network, provide both invasive and noninvasive options for CRC screening.While the American College of Gastroenterology considers colonoscopy to be preferred, other professional organizations recommend all options without preference.[12][13][14][15] Despite these recommendations and patients' preference for noninvasive screening in several studies, providers are more likely to recommend colonoscopy and may not present other options.[16][17][18] Patients who choose colonoscopy report doing so because of its superior single-application sensitivity, as reflected in statistics on its use, 19 while those that do not choose it report many reasons including difficulty in scheduling, cost, and missed work time in addition to concerns of modesty, procedure discomfort, and bowel preparation.20 Colonoscopy also carries risk, such as bleeding, perforation, and cardiorespiratory complications.Although the risks are low, they are particularly relevant for patients with comorbid conditions 21 and may affect adherence.In an attempt to improve CRC screening and make available additional options without the