(5) Operation procedure：①Bowel preparation consisted of patients drinking a total of 4 L of polyethylene glycol solution before their procedures.Until the discharge of clean liquid (colorless or yellow transparent water samples). ②Total colonoscopies were prospectively performed by using a high-definition endoscope (CF-H260AL; Olympus Co, Tokyo, Japan) by 7 highly experienced endoscopists. All polyps found during colonoscopy were photographed, and their characteristics, including size,shape and anatomic location, were documented. The size of the polyp was assessed with the width of the biopsy forceps before the polyps were removed. ③Polyps that were deemed neoplastic (vessels surrounding oval, tubular, or branched pits under observation by high-definition white-light endoscopy and narrow-band imaging endoscopy) were subjected to polypectomy. Polyp size was defined by using the opening width of the biopsy forceps. If the size of the polyp was eligible for the study (3-9mm), polypectomy was performed by one of two randomized methods.④ Two kinds of operation methods are adopted: 1.CSP was performed by using a disposable oval snare with a diameter of 10 mm (SD-210U-10; Olympus) under gentle suction to reduce colon wall tension. The tip of the endoscope was deflected toward the polyp base to ensnare 1 to 2 mm of normal mucosa surrounding the polyp.2.HSP, which is using electrocoagulation on the basis of using cold snare.⑤After the polyps were removed, the ulcers were washed with saline lavage fluid. After that, another independent endoscopic surgeon judged whether the endoscopic eradication was successful. ⑥Afterward, additional EMR was performed at the polypectomy site to evaluate for the presence of residual polyp tissue.For histologic assessment of residual polyp tissues, the polypectomy site, including an additional 1 to 2 mm clear margin, was resected by the snare and Endocut current (VIO300D; Erbe Elektromedizin GmbH, Tubingen, Germany) after submucosal injection of a mixed solution (normal saline solution + 0.01% epinephrine). In the event that no tissue could be removed (e.g., if the original resection achieved a wide resection), or if EMR failed to get in situ mucosal specimens. At least four cold biopsies using forceps on the remaining margins were obtained. The primary polyp specimen and the specimen from the base of the polyp were placed in separate jars.⑦After each procedure, the polypectomy site was observed for 30 seconds to confirm the absence of immediate bleeding, the specimens were retrieved and stored in formalin.⑧The retrieved specimen was fixed on a plate by using pins. After indigo carmine solution was applied, the specimen was studied under a stereomicroscope with 8-power magnification to assess the presence of residual tissue by the endoscopist who performed the polypectomy. The presence of residual tissue was documented, and the plate was marked with a pen to indicate the most probable site of residual tissue. Cross-sections of the EMR specimens were collected at 1-mm intervals; accurate tissue section of the marked site was ensured. ⑨All tissue samples were cross-reviewed by 2 experienced pathologists who were blinded to the clinical information. Histological identification was carried out and the comprehensive analysis was carried out. The process is shown in Figure 1. ⑩The patients returned 1 week after each polypectomy to be informed of their pathology results and to be assessed for postprocedural adverse events, such as delayed bleeding. Complete resection was defined as the absence of residual polyp tissue in the EMR sections of the polypectomy site.