Virtual colonoscopy (also known as CT colonography or CTC) is effective in older screening subjects and does not result in a high rate of referral to invasive colonoscopy, according to a new study published in the February issue of Radiology.
The findings are the product of a multiyear analysis by lead author Dr. David Kim from the University of Wisconsin in Madison (Radiology, February 2010, Vol. 254:2, pp 493-500). The study was first presented at the International Symposium on Virtual Colonoscopy in Reston, VA, in November 2009.
The researchers studied 577 individuals, analyzing performance and program outcome measures of screening VC in individuals ages 65 to 79 (mean age, 69.2 years ± 3.8) from a total of 5,176 individuals of all ages screened for colorectal polyps and cancer.
The group classified all polyps 6 mm and larger as positive findings, requiring either surveillance (patients with two or fewer polyps smaller than 10 mm) or referral to optical colonoscopy (OC) for removal (patients with polyps 10 mm and larger).
The overall referral rate to optical colonoscopy was 15.3% (88 of 577), resulting in 277 polypectomies and the removal of 103 adenomas 6 mm in diameter or larger. Overall positivity was 10.9% (63 of 577) at the 6-mm polyp threshold and 6.8% (39 of 577) at the 10-mm polyp threshold.
"Nearly 85% (489 of 577) of individuals in this age range who are screened with CT colonography avoid the need for OC, thus decreasing the possibility of major OC complications that are known to be increased in this older cohort," Kim and colleagues wrote.
Advanced neoplasia was found in 7.6% (44 of 577) of patients. Fifty-four adenomas had advanced histology (most being large at 21-mm mean diameter), and five unsuspected cancers were detected. Potentially important extracolonic findings were found in 15.4% (89 of 577) of patients (including 18 vascular aneurysms), with a workup rate of 7.8% (45 of 577). There were no major complications from virtual colonoscopy.
The study confirms the utility of virtual colonoscopy in the Medicare population, the researchers concluded. The U.S. Centers for Medicare and Medicaid Services (CMS) rejected reimbursement for CTC studies of Medicare patients in May 2009.
"This study shows that CTC is a viable screening exam in all age groups," Kim said in a statement accompanying the publication. "We are hopeful now that the remaining questions regarding older patients have been answered, patients will have wider access to CTC, more will be screened for colorectal cancer, and more lives can be saved as a result," he said.
By Eric Barnes
AuntMinnie.com staff writer
January 27, 2010
Related Reading
NIH issues $2.7M grant on VC screening, January 19, 2010
VC screening maintains performance in Medicare population, November 9, 2009
Meta-analysis reveals paucity of advanced neoplasia in small polyps, November 2, 2009
VC CAD nabs undetected polyps in jumbo screening study, October 29, 2009
Risks from colonoscopy in elderly increase with age, comorbidities, July 13, 2009
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