Extracolonic Findings on Screening CTC Rare, but Significant

February 3, 2016

Screening CTC rarely finds extracolonic findings among asymptomatic patients, but many are clinically significant.

Extracolonic findings detected during CT colonography (CTC) screening of asymptomatic patients are not common, but when found, they are often clinically significant, according to a study published in the American Journal of Roentgenology.

Researchers from the University of Wisconsin School of Medicine and Public Health in Madison sought to analyze the incidence and outcome of unsuspected significant extracolonic findings in the CT Colonography Reporting and Data System (C-RADS), classified as E4 findings, among patients who  were undergoing CTC screening.

A total of 7,952 patients (3,675 men and 4,277 women), mean age of 56.7, participated in the study that took place between April 1, 2004 and June 30, 2012. All patients were undergoing screening for the first time. Potentially significant findings were retrospectively reviewed with additional analysis of follow-up of between two and 10 years and ultimate clinical outcome.

The results showed that 202 of the patients (2.5%) had a potentially significant (C-RADS category E4) extracolonic finding, but none had multiple E4 findings. Of these patients, 113 (56%) were recommended for further imaging and 89 (44%) for clinical follow-up. No patients had multiple category E4 findings. Of 180 patients (22 patients were lost to follow-up), 123 patients (68%) were found to have clinically significant disease; 42 (23%) and 57 patients (32%) with abdominal aortic or other visceral artery aneurysms requiring treatment or surveillance.

Most commonly involved organs and systems:

Organs and systemsNumber of patients affected, of 202
Vascular system53 (26%)
Genitourinary system36 (18%)
Liver30 (15%)
GI system20 (9.9%)
Lungs19 (9.4%)
Gynecologic system14 (6.9%)

“Potentially significant extracolonic findings in asymptomatic adults at screening CTC are uncommon (2 to 3 percent of cases),” the researchers wrote. “However, most of these findings (68%) will prove to be clinically significant, including a number of malignancies and aneurysms requiring treatment or surveillance.”