Five years ago, the U.S. Preventive Services Task Force (USPSTF) determined there was insufficient evidence to support national reimbursement of screening colonography. Multiple studies published in the interim address the USPSTF’s concerns and support a change in rating, according to a review published in the July issue of American Journal of Roentgenology.
When USPSTF rated screening CT colonography “I” for insufficient, the organization cited three primary concerns: radiation dose, extracolonic findings and generalizability to senior citizens, explained Judy Yee, MD, department of radiology and biomedical imaging, San Francisco VA Medical Center, and colleagues.
“CTC is an extremely low-dose procedure,” wrote Yee et al. The effective dose of the exam is approximately 3 mSv or less when state-of-the-art CT technology and dose-lowering tools are employed.
Since 2008, 10 studies, including two large multicenter trials, have focused on extracolonic findings. In an average-risk population of 605 individuals, findings in 16 percent of participants were categorized as indeterminate, and 5.5 percent of the cohort proceeded to additional workup. These rates are similar to those observed in screening programs in Wisconsin and at Walter Reed Army Medical Center in Washington, DC.
In a large multicenter Dutch trial, 11 percent of the 982 individuals who underwent CT colonography had results categorized as indeterminate or potentially clinically significant, and 9.6 percent underwent additional exams.
Yee and colleagues noted that the use of structured reporting can help to keep incidental extracolonic findings in the low range. Additionally, complications from follow-up workups are “likely low.”
Since 2008, four studies have evaluated screening colonography in senior patients. The results show:
- a concordance rate of 91 percent between CT colonography and optical colonography;
- comparable polyp prevalence according to size when comparing senior and nonsenior patients;
- comparable sensitivity and specificity by polyp size for senior and nonsenior patients; and
- comparable referral rates to colonoscopy for senior and nonsenior patients.
“CTC has already been endorsed by the American Cancer Society, the U.S. Multi-Society Task Force, and the ACR as a valid test for CRC screening. National reimbursement will allow more rapid and widespread dissemination of CTC to the public, which will result in improved CRC screening adherence and ultimately in more lives saved,” Yee and colleagues concluded.