Virtual Colonoscopy Effective for Screening Older Patients

Abstract

Computed tomographic colonography (CTC) remains effective in screening older patients for colorectal cancer (CRC), produces low referral for colonoscopy rates similar to other screening exams now covered by Medicare, and does not result in unreasonable levels of additional testing resulting from extracolonic findings, according to a study published in the February 2010 issue of Radiology. Previous CTC trials have demonstrated excellent performance in average-risk individuals. However, concerns remained that such results may not be applicable to older Medicare beneficiaries. Researchers at the University of Wisconsin School of Medicine and Public Health analyzed various CTC performance and program outcome measures for screening individuals aged 65–79. “These results confirm that CTC is a safe and effective colorectal cancer screening tool for the older individual. There is no significant difference in the way CTC performs in older patients as opposed to younger patients,” said David H. Kim, MD, Associate Professor of Radiology at the University of Wisconsin School of Medicine and Public Health, and principal investigator of the study. In the study, for this older screening group, the prevalence of advanced neoplastic lesions was 7.6% (44 of 577). There was no significant difference between older patients and the general screening population in terms of the characteristics of advanced neoplasia—including mean size, histologic type, and morphology—indicating similar accuracy to that found in other trials involving younger patients. The overall referral rate to optical colonoscopy of 15.3% (88 of 577) is actually slightly lower than other Medicare covered CRC screening exams such as flexible sigmoidoscopy. Potentially important extracolonic findings were seen in 15.4% of patients (89 of 577), with a work-up rate of 7.8% (45 of 577). The majority of important extracolonic diagnoses were vascular aneurysms (n = 18). No major complications were encountered. The authors note that CTC is now one of the preferred options in the American Cancer Society colorectal cancer screening guidelines. They point to the possibility that the recent addition of CTC may have a major effect on future public health, “as up to 40% of the eligible population does not undertake screening with the traditional options. Reported screening adherence is even worse for the older cohort of Medicare patients.” “The lack of complications, particularly no perforations, attests to the safety of this procedure even in the older population,” said Kim. “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.” See: Radiology, 2010;254:493–500; http://radiology.rsna.org/content/254/2/493.full.