Inclusion Criteria:  Age older than 20 years old Indicated for colonoscopy and willing to receive colonoscopy examination and polyp resection。 Any Sessile serrated adenoma size between 10-20mm was found during the examination。  Exclusion Criteria:  Age younger than 20 years old Contraindication for colonoscopy or polypectomy (Such as recent acute myocardial infarction, pulmonary embolism ,coagulopathy..)