The National CT Colonography Trial recruited 2,600 study participants ages 50 and over from 15 US medical centers to compare the accuracy of state-of-the-art CT colonography to the gold standard of conventional colonoscopy. Ninety percent of the polyps 1 centimeter or larger—the polyps most likely to become cancerous—were detected by CT colonography. Polyps as small as one-half centimeter were also detected by CT colonography with a high degree of accuracy.
In the secondary analysis of the 65 and over cohort, data were available for 477 study participants. The percentage of participants with large polyps was significantly greater among the older participant group (3.7 percent for aged < 65 vs. 6.9 percent for > 65); however, even if intermediate-sized polyps of 6mm or larger were targeted for removal with standard colonoscopy, the colonoscopy referral rate would not exceed 12.6 percent.
ACRIN Chair Mitchell J. Schnall, MD, PhD, Matthew J. Wilson Professor of Research Radiology at the University of Pennsylvania, comments, “These results demonstrate the wealth of data that are collected in ACRIN clinical trials that can be used to explore important cancer screening and other research questions. For example, ACRIN has undertaken another study leveraging the National CT Colonography Trial data investigating the prevalence and type of incidental findings reported as part of a CT colonography examination to better understand their impact and to develop guidelines for the reporting and management incidental findings."
CT colonography employs virtual reality technology to produce a three-dimensional visualization that permits a thorough and minimally invasive evaluation of the entire colon and rectum. The ACRIN trial is the largest multi-center study to compare the accuracy of state-of-the-art CT colonography to the gold standard of conventional colonoscopy in patients 50 and older. Colorectal cancer is the third most frequently diagnosed cancer and second leading cause of cancer death in men and women in the United States. Yet, despite the known benefits of screening, studies indicate that millions of Americans age 50 and older are not being screened for the disease.
ACRIN is a NCI Clinical Trials Cooperative Group. It is made up of investigators from over 100 academic and community–based medical facilities in the United States and several international institutions. ACRIN’s mission is to develop information, through clinical trials of diagnostic imaging and image-guided therapeutic procedures that will result in: 1) the earlier diagnosis of cancer, 2) allaying the concerns of those who do not have cancer, and 3) improving the length and quality of lives of cancer patients.