Early Detection of Colorectal Cancer: Conventional Techniques and Current Biomarkers

Colorectal cancer (CRC) is the third most common cancer worldwide, and the incidence of CRC seems to increase gradually. The survival of CRC varies in different countries, attributed to the screening program. Generally, diagnostic approaches for CRC can be divided into visual detection methods and laboratory methods. Colonoscopy, sigmoidoscopy, and computed tomography colonography are considered visual methods widely used in cancer detection. Although visual methods provide some benefits, some disadvantages such as late detection, are present, making them useless in rapidly progressing CRC patients. On the other hand, laboratory tests are developed to compensate for the disadvantages of visual methods. More recent progression in laboratory tests makes them able to superfine detection of CRC. For instance, molecular and genetic methods based on the components of cancer cells, like nucleic acid and proteins, can prognosticate further cancer development in susceptible patients. Alongside new therapeutic approaches developed within decades, the number of CRC detection methods has increased, which aims to reduce the duration between cancer initiation and detection. This review sought to survey the CRC detection methods, including conventional and recently-developed methods, to provide better insight into CRC screening.