BACKGROUND The official guidelines are unclear about whether endoscopic polypectomy should intubate the whole cecum or just intubate the location of the endoscopy inspection. Therefore, the objective of this study was to provide a new perspective of assisting endoscopists make better decisions and decrease the missing detection rate in clinical practice. MATERIAL AND METHODS We retrospectively reviewed records of 8923 patients who underwent endoscopic polypectomy, and 394 participants were included after screening by inclusion and exclusion criteria. We collected and analyzed data on the size, shape, and location of polyps and the clinical experience level of endoscopists in this retrospective study. RESULTS Among the 394 cases, 152 (38.6%) had additional lesions detected through the second endoscopic polypectomy after the first colonoscopy was performed, showing statistically significant differences between the missing group and non-missing group on actual polys (P<0.05). No significant differences were detected between the 2 groups (P>0.05) in age, sex, withdrawal time, and examination period. Regarding the location, 50.4% of the missing lesions were found on the relatively proximal colon of the detected polyps in the first colonoscopy. In addition, the level of experience of endoscopists was significantly different between the missing group and the non-missing group (P<0.05). CONCLUSIONS The characteristics of polyps and the level of endoscopist experience play important roles in the detection of polyps in the colorectum. Moreover, it may be necessary to intubate the cecum to examine the whole colorectum during endoscopic polypectomy.