Performance and Evaluation for CT Colonography Screening

Colorectal cancer (CRC) is an important United Kingdom healthcare issue affecting 1 in 20 individuals, half of whom will die from the disease. Late presentation of CRC has a poor prognosis, whereas excellent cure rates (\>95%) are seen in those who present early. Accurate and early diagnosis of CRC is therefore crucial. In most patients this is achieved via colonoscopy, a camera test which is widely available and allows tissue samples to be taken of any abnormalities seen during the procedure. However, a non-invasive alternative is Computed Tomography Colonography (CTC) which uses X-rays to produce images of the large bowel which are then interpreted by Radiologists. CTC has high sensitivity for the diagnosis of CRC (comparable to colonoscopy) and the cancer precursor - adenomatous polyps. Unlike colonoscopy, however, there is no accreditation process for CTC and there is no infrastructure to ensure that all reporting Radiologists are able to do so adequately and, as a result, there is a wide range of diagnostic accuracy. There are no universally-accepted standards to monitor quality or assess diagnostic performance, partly because we do not know what the quality markers are and there is currently no system to quantify them. Overall, this contributes to low cancer detection rates, missed cancers and inequity for patients across the National Health Service (NHS). This study aims to assess the impact of a structured training programme with assessment and feedback on NHS radiologist performance. If the impact is positive and results in significantly improved performance, then such a scheme could be adopted into an accreditation programme for CTC in the English Bowel Cancer Screening Programme (BCSP).