CT Colonography Reporting and Data System (C-RADS): Benchmark Values From a Clinical Screening Program

Abstract

OBJECTIVE The CT Colonography Reporting and Data System (C-RADS) is a well-recognized standard for reporting findings at CT colonography (CTC). However, few data on benchmark values for clinical performance have been published to date, especially for screening. The purpose of this study was to establish baseline C-RADS values for CTC screening. SUBJECTS AND METHODS From 2005 to 2011, 6769 asymptomatic adults (3110 men and 3659 women) 50–79 years old (mean [± SD] age, 56.7 ± 6.1 years) were enrolled for first-time CTC screening at a single center. CTC results were prospectively classified according to C-RADS for both colorectal and extracolonic findings. C-RADS classification rates and outcomes for positive patients were analyzed. RESULTS C-RADS classification rates for colorectal evaluation were C0 (0.7%), C1 (85.0%), C2 (8.6%), C3 (5.2%), and C4 (0.6%). Overall, 14.3% of subjects were positive (C2–C4), and positive findings were more frequent among men (17.5%) than women (11.6%; p< 0.0001). Positivity also increased with age, from 13.4% of patients 50–64 years old to 21.8% of patients 65–79 years old (p< 0.0001). Regarding extracolonic evaluation, 86.6% of patients were either negative for extracolonic findings or had unimportant extracolonic findings (E1 or E2). Likely unimportant but indeterminate extracolonic findings where further workup might be indicated (E3) were found in 11.3% of patients, whereas 2.1% had likely important extracolonic findings (E4). Overall, E3 and E4 rates were increased for older (p< 0.0001) and female (p= 0.008) cohorts. CONCLUSION C-RADS results from our initial experience with CTC screening may serve as an initial benchmark for program comparison and quality assurance measures.

Indeterminate but Likely Unimportant Extracolonic Findings at Screening CT Colonography (C-RADS Category E3): Incidence and Outcomes Data From a Clinical Screening Program

“…[16, 17] The present study essentially confirms this previous figure, as 927/7952 patients (11.7%) of our total population had either C-RADS category E3 (N=202) or E4 (N=725) findings, leaving the remaining 7025/7952 patients (88.3%) without clinically relevant extracolonic findings (C-RADS category E1 or E2). Despite persistent concern for a large number of follow-up imaging studies, the actual work up rate for all reported extracolonic findings has consistently been less than 10% in large CTC series.…”

Potentially Important Extracolonic Findings at Screening CT Colonography: Incidence and Outcomes Data From a Clinical Screening Program

“…[18] Of the remaining patients with findings that may be clinically relevant, a majority have extracolonic findings which are deemed likely insignificant (C-RADS extracolonic category E3), with only a small minority of patients demonstrating potentially significant extracolonic findings (C-RADS extracolonic category E4). Despite the concern for substantial numbers of required additional studies, the actual work up rate for all reported extracolonic findings has consistently been less than 10% in large CTC series.…”

Colorectal cancer

“…However, CT colonography has low sensitivity for small (6–9mm) and flat lesions 101 . The technique is associated with high colonoscopy referral rates (up to 30%), and high rates of extra-colonic findings in non-cancer cases, which translate to unnecessary investigations and increased anxiety for individuals 102,103 . The costs of CT colonography, and the need for further investigation in a subset of screenees limit the usefulness of this method for population screening in most countries.…”