Adenoma detection rate: is it the master key for the colonoscopy quality indicator?

Colonoscopy is the most important method for preventing colorectal cancer (CRC) (1). However, colonoscopy is also known to be not flawless technique. According to back-toback colonoscopy study, a quarter of polyps were missed during colonoscopy (2). In spite of technical improvement, there has been no decrease in the occurrence of missed or early CRC over a 10-year period (3). In addition, the main cause of post-colonoscopy CRCs (PCCRCs) is not completely new lesions but missed lesions (4). The most crucial cause of this phenomenon is the endoscopist related factor. As we already perceive, colonoscopy performance is variable.