Lower gastrointestinal symptoms attributed to colorectal disease are common. Early diagnosis of serious colorectal disease such as colorectal cancer (CRC), precancerous growths (polyps) and inflammation is important to ensure the best possible outcomes for a patient. The current ‘gold standard’ diagnostic test is colonoscopy. Colonoscopy is an invasive procedure. Some people struggle to cope with it and require intravenous sedation and/or analgesia. It is also resource-intensive, needing to be performed in specialist endoscopy units by a trained team. Across the UK, the demand for colonoscopy is outstripping capacity and the diagnosis of colorectal disease is being delayed. A colon capsule endoscope (CCE) is an alternative colorectal diagnostic. It is a ‘camera in a pill’ that can be swallowed and which passes through the gastrointestinal tract, obtaining visual images on the colon. There is now established experience of CCE in the UK. CCE might provide a less invasive method to diagnose colorectal disease if found to be accurate and effective and provide a means by which to increase the National Health Service (NHS) diagnostic capacity.

The aim of this study is to determine the diagnostic accuracy of CCE when compared with colonoscopy in representative and clinically meaningful cohorts of patients. An evaluation of the experiences of CCE for the patient and clinical team and an assessment of cost effectiveness will be undertaken.

We will undertake three research workstreams (WS). In WS1, we shall perform a paired (back-to-back) study. Each participant will swallow the CCE and then later on the same day they will have a colonoscopy. The study has been designed in collaboration with our Patient Advisory Group and as closely mirrors standard care as is possible. 973 participants will be recruited from three representative clinical contexts; suspected CRC, suspected inflammatory bowel disease and postpolypectomy surveillance. Up to 30 sites across the UK will be involved to maximise inclusivity. Measures of diagnostic accuracy will be reported along with CCE completion rates, number of colonoscopy procedures potentially prevented and adverse events, such as capsule retention. A nested substudy of intraobserver and interobserver agreement will be performed. WS2 will develop models of cost-effectiveness and WS3 will evaluate the patient and clinician experience, with reference to acceptability and choice.

The study findings will provide the evidence base to inform future colorectal diagnostic services.

The study has approval from the North East—Tyne and Wear South research ethics committee (REC reference 24/NE/0178, IRAS 331349). The findings will be disseminated to the NHS, National Institute for Health and Care Excellence, other clinical stakeholders and participants, patients and the public.

ISRCTN16126290.