This study will evaluate the efficacy and safety of cold snare polypectomy(CSP) and hot snare polypectomy(HSP) in the treatment of colorectal 4-9mm 0-Isp and 0-Ip polyps, and compare the complete resection rate, postoperative late bleeding rate, intraoperative bleeding rate, en bloc resection rate, operation time and the number of metal clips used. The conclusion of this study will help clinical doctor develop more effective resection strategies for colorectal 0-Isp and 0-Ip polyps, and provide more effective treatment for patients.

Colorectal polyps are one of the precancerous lesions of colorectal cancer, 60-80% of which eventually become advanced colorectal cancer. Therefore, early resection of colorectal polyps can effectively reduce the incidence of colorectal cancer. Polyps under white light are judged mainly according to the shape, size and color of polyps. At present, the Paris classification is often used to divide 0-I uplifted polyps into sessile polyps (0-Is), sessile-pedunculated polyps (0-Isp) and pedunculated polyps (0-Ip). It is generally believed that there are thick arteries in 0-Ip polyps, especially thick pedunculated polyps, which are prone to uncontrollable bleeding during operation. 0-Is polyps have small scattered blood vessels and low intraoperative bleeding risk, while the morphological and structural characteristics of 0-Isp polyps are between the two. The current guidelines recommend HSP for 0-Isp and 0-Ip polyps <1 cm, but the internal blood vessels of these polyps are not thick. There is no guidance on whether they can be resected by CSP method, and there is a lack of prospective large sample clinical research. This study will include0-Isp /0-Ip polyps <1cm, and observe the safety and effectiveness of CSP for the above polyp resection , so as to provide reference for the clinical treatment of colorectal polyps.

Inclusion Criteria:

1. Age: 18-80 years old, male or female
2. At least one polyp with size of 4-9 mm 0-Isp or 0-Ip is found during colonoscopy
3. Voluntarily sign informed consent for endoscopic treatment

Exclusion Criteria:

1. Boston Bowel Preparation Scale<6 points.
2. Patients who receive antiplatelet/anticoagulant therapy within 5 days before polypectomy.
3. Participants with a contraindication to colonoscopy and polypectomy.
4. Patients with inflammatory bowel disease or gastrointestinal polyposis.
5. Lesions with submucosal invasion and those suspected of being cancerous at the preprocedural diagnostic evaluation.
6. Patients with pregnancy.