ABSTRACT
OBJECTIVES: CT Colonography (CTC) is being increasingly used for the radiological evaluation of colorectal symptoms. Aim of this study was to assess the role of CTC in excluding a colorectal cancer (CRC) in older symptomatic patients. METHODS: 1,359 CTC studies performed between March 2002 and December 2007 were analysed retrospectively. Gold standard was an endoscopic examination within 1 year and/or clinical, endoscopic and/or radiological follow-up until the time of data analysis. Patients not diagnosed as having a CRC on CTC were assumed as true-negatives if the gold standard was negative and did not feature on the regional cancer registry (at least 18 months post-CTC). Sensitivity, specificity, positive and negative predictive values were calculated for detection of colorectal cancer. RESULTS: After exclusions, 1,177 CTC studies were included. These were undertaken in 463 men and 714 women. Median age of patients undergoing CTC was 71 (range, 27-96) years. 59 invasive CRC were detected. Median follow-up was 34.5 (range 18-84) months. Three small colorectal cancers were missed. Sensitivity and negative predictive value for CRC were 94.9% (95% CI:84.9%-98.7%) and 99.7% (95% CI:99.1%-99.9%) respectively. CONCLUSIONS: CTC has a high sensitivity and negative predictive value in excluding a CRC in patients with colorectal symptoms.
