Indications and evidence for CTC

The clinical indications of CTC have broadened gradually over the past decade. Several interactive influences of this trend include the impact of validation data of clinical trials, health policy decisions of colorectal screening guidelines, and insurance reimbursement rates determined by payors. After the early clinical trials of CTC in the late 1990s, clinical use of CTC was limited to a few specific diagnostic indications [1]. Since 2003 with the emergence of multiple successful large screening trials, there has been broader use of CTC in asymptomatic patients. From these validation data however, health policy agencies responded differently in 2008 for the 5-year updates of colorectal screening guidelines. Specifically, the American Cancer Society, with the multidisciplinary consensus of the American College of Radiology and the US Multi-Society Task Force of colorectal cancer (comprised of the American Gastroenterology Association, American Society of Gastroenterology, and the American College of Gastroenterology), recommended the use of CTC for the first time for screening of average-risk patients [2]. Contrary to this, the US Preventative Task Force (USPTF) gave CTC an indeterminate rating of effectiveness and did not recommend CTC for screening purposes [3].