Computed tomographic colonography is a noninvasive option in screening for colorectal cancer.
However, its accuracy as a screening tool in asymptomatic adults has not been well defined.
Dr Daniel Johnson and colleagues from Arizona, USA recruited 2,600 asymptomatic study participants, 50 years of age or older, at 15 study centers.
Computed tomographic colonographic images were acquired with the use of standard bowel preparation, stool and fluid tagging, mechanical insufflation, and multidetector-row computed tomographic scanners.
Radiologists trained in computed tomographic colonography reported all lesions measuring 5 mm or more in diameter.
|The sensitivity for computed tomographic colonography was 90%|
|New England Journal of Medicine|
The team performed optical colonoscopy and histologic review according to established clinical protocols at each center and served as the reference standard.
The primary end point was detection by computed tomographic colonography of histologically confirmed large adenomas and adenocarcinomas, 10 mm in diameter or larger that had been detected by colonoscopy.
Detection of smaller colorectal lesions, 6 to 9 mm in diameter, was also evaluated.
The researchers found complete data for 2531 participants.
For large adenomas and cancers, the mean per-patient estimates of the sensitivity, specificity for computed tomographic colonography were 90% and 86%, respectively.
The team noted that positive and negative predictive values, and area under the receiver-operating-characteristic curve for computed tomographic colonography were 23%, 99%, and 89%, respectively.
The team report that the sensitivity of 90% indicates that computed tomographic colonography failed to detect a lesion measuring 10 mm or more in diameter in 10% of patients.
The per-polyp sensitivity for large adenomas or cancers was 84%.
The researchers observed that the per-patient sensitivity for detecting adenomas that were 6 mm or more in diameter was 78%.
Dr Johnson’s team concluded, “In this study of asymptomatic adults, computed tomographic colonographic screening identified 90% of subjects with adenomas or cancers measuring 10 mm or more in diameter.”
“These findings augment published data on the role of computed tomographic colonography in screening patients with an average risk of colorectal cancer.”