Study: CT colonography just as effective for older patients

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CT colonography, or virtual colonoscopy, is a safe and effective screening modality for the older patient population in the screening of colorectal cancer (CRC), according to the findings of a retrospective analysis published in the February Issue of Radiology.

Unlike other screening exams which are covered by Medicare, CT colonography produces low referral for colonoscopy rates and does not result in high levels of additional testing, said David Kim, MD, associate professor of radiology at the University of Wisconsin’s School of Medicine and Public Health in Madison, and colleagues.

Researchers assessed the medical records of the CT colonography screening program at the University of Wisconsin, which consisted of 5,176 participants. Of this sample size, a cohort of 577 participants between the ages of 65 to 79 was further analyzed. The authors noted advanced neoplasia prevalence and colonoscopy referral, extracolonic finding, extracolonic work-up and complication rates as outcome measures for their study.

In the HIPAA-compliant study, investigators compared the outcome measures of the individuals in the older cohort to the rest of the study population and found that no major complications due to CT colonography were encountered in either patient group.

In the older patient cohort, the advanced neoplastic prevalence was 7.6 percent and the neoplasias were found to be typically large in size (mean size, 21 mm). However, the authors noted that this finding was not significant in terms of statistical difference between the older patient group and the rest of the screening population.

Additionally, the authors wrote that the overall referral rate to optical colonoscopy of 15.3 percent is slightly lower than other Medicare covered CRC screening exams, including flexible sigmoidoscopy.

Other findings included the majority of important extracolonic diagnoses were found to be vascular aneurysms and potentially important extracolonic findings were seen in 15.4 percent of patients, with a work-up rate of 7.8 percent. Moreover, five unsuspected cancers were detected by way of CT colonography screening.

"There have been questions raised that factors such as the [colonoscopy] referral rate and extracolonic work up rates would be too high in an older population for CT colonography to be a cost-effective, frontline CRC screening exam,” said Kim. “Our results suggest otherwise and that these rates remain in a reasonable range.”

The researchers noted that although no significant difference was found in the way CT colonography performs within either patient population, according to the results of their study, older patients could potentially have wider access to this screening method.

"The lack of complications, particularly no perforations, attests to the safety of this procedure even in the older population,” concluded Kim and colleagues. “Given what we know of the increasing risk for complications for optical colonoscopy in older patients, perhaps we should consider CT colonography more strongly in this particular group.”