Colorectal cancer: prevention and early diagnosis

Colorectal cancer (CRC) is one of the leading causes of cancer deaths worldwide. This article reviews the aetiology and risk factors for CRC and focuses on strategies for prevention and early diagnosis. Prevention involves identifying and optimizing modifiable risk factors through public health awareness as well as population screening, for example using detection of occult blood in stool. Endoscopic surveillance in the UK is currently performed on a population basis with the bowel scope programme and faecal immunochemical testing, with colonoscopy reserved for patients known to be at higher risk of developing CRC. These include individuals with genetic predisposition or long-standing inflammatory bowel disease. Population screening for CRC is well established in clinical practice as an effective method for early cancer detection and prevention through polypectomy. It is effective at improving disease stage at diagnosis and thus reducing CRC-specific mortality. Recent changes to the NHS screening programmes and advances in the understanding of the serrated pathway for CRC development are highlighted and their respective roles for cancer prevention discussed. Finally, future directions in technology and research for prevention and early diagnosis of CRC, including computer-aided diagnosis (deep learning), are explored