Gastrointestinal polyps of 0.4cm to 0.5cm are at the level of common polyp sizes and are not considered to be too large in diameter. In general, polyps in the gastrointestinal tract up to 5 mm (0.5 cm) in diameter are more common and are more likely to be considered benign, but the severity of polypoid lesions cannot be determined by the size of the polyp alone, and there are different pathologic types as well. If the pathologic type is adenomatous polyp, it is relatively serious, while other types such as hyperplastic polyp and inflammatory polyp are less serious. For gastrointestinal polyps of 0.4cm to 0.5cm, the size of which is at the level of common polyp diameters, endoscopic polypectomy can be performed to further clarify the pathologic typing of polyp lesions and to detect the risk of cancer at an early stage.