Radiology: Volume 254: Number 2—February 2010
David H. Kim, MD Perry J. Pickhardt, MD Meghan E. Hanson, MD J. Louis Hinshaw, MD
Purpose: To evaluate computed tomographic (CT) colonography performance and program outcome measures in an older cohort (63-79 years) of an established large-scale colorec¬tal cancer screening program.
Materials and Methods: This HIPAA-compliant study was approved by the institu¬tional review board; informed consent waived. Retrospec¬tive analysis of the 65-79-year-old cohort (n = 377) from the University of Wisconsin CT colonography screening program (n = 3176) was undertaken. Performance and outcome measures including advanced neoplasia preva¬lence and colonoscopy referral, extracolonic finding, ex-tracolonic work-up, and complication rates were obtained by using a CT colonography database and review of medi¬cal records. Comparisons between the older cohort and the general screening population were made by using the Student t, Pearson x2 , and Fisher exact tests. A P value = .05 was considered to indicate a significant difference.
Results: With a 6-mm threshold for positivity, the overall referral rate to optical colonoscopy was 15.3% (88 of 577), leading to 277 polypectomies and the removal of 103 nondiminu-tive adenomas. For adenomas, the per-patient positivity rates were 10.9% (63 of 577) and 6.8% (39 of 577) at the 6- and 10-mm thresholds, respectively. The prevalence of advanced neoplasia was 7.6% (44 of 577). Fifty-four ade¬nomas met advanced status, and five unsuspected cancers were detected. The advanced neoplasias identified were typically large, with a mean size of 21 mm. Potentially important extracolonic findings were seen in 15.4% (89 of 577) of patients, 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.
Conclusion: CT colonography is a safe and effective screening modality for the older population.