Extracolonic abnormalities discovered incidentally at CT colonography in a male population

Abstract

Purpose: To evaluate prospectively the prevalence of incidental extracolonic findings at computed tomographic (CT) colonography and to estimate the cost of their imaging work-up in male patients with high and those with average risk of colorectal cancer.

Materials and methods: This study was approved by the institutional review board, and informed consent was obtained from all patients. The study was compliant with requirements of the Health Insurance Portability and Accountability Act. CT colonography was performed in 500 men (mean age, 62.5 years). Of these patients, 194 (38.8%) were at average risk for colorectal cancer and presented for routine screening. The other 306 (61.2%) were at high risk for colorectal cancer. Extracolonic findings were recorded and categorized as either clinically important or clinically unimportant. Clinically important findings were defined as those that necessitated further diagnostic studies or medical or surgical follow-up. The cost of additional imaging required to further characterize important lesions was estimated. Chart review was performed (mean length of follow-up, 3.6 years) to determine whether any important findings were missed at CT colonography. The Fisher exact test was used to determine whether there was a difference between the percentages of average- and high-risk patients with extracolonic findings.

Results: Of the 500 patients in the study, 315 (63.0%) had extracolonic findings, and 45 (9.0%) had clinically important extracolonic findings. Of the 596 extracolonic findings identified, 50 (8.4%) were thought to be clinically important. The mean additional cost to work up important findings was $28.12 per CT colonographic examination. There were no significant differences between average-risk and high-risk patients in the percentages of extracolonic findings (P = .25) or clinically important extracolonic findings (P = .11).

Conclusion: A substantial number of both average- and high-risk patients undergoing CT colonography will be found to have clinically important extracolonic findings. There was no increased morbidity or mortality associated with the additional evaluation of extracolonic findings. The cost of evaluating these lesions is low, given the potential for positive effects on patient care.