A prospective, randomized, controlled study to compare the efficacy and safety of underwater endoscopic mucosal resection and conventional endoscopic mucosal resection in removal of non-pedunculated colorectal polyps

• Patients are undergone colonoscopy at the Endoscopy department of Ho Chi Minh City University Medical Center.
• Randomize patients with non-pedunculated polyp of 10mm or larger in size into 2 interventional groups based on Random function of Statistical Package for the Social Sciences (SPSS) 20.0, including (1) Group 1: Underwater endoscopic mucosal resection (UEMR) and (2) Group 2: Conventional endoscopic mucosal resection (CEMR).
• The time of local recurrence assessment depends on the histopathology of polyps. Polyps with low grade dysplasia are followed up at 6 months, while polyps with high grade dysplasia are followed at 3 months.
• Collecting variables which consist of primary and secodary outcomes.

Inclusion Criteria:

• Age > 18 years
• Non-pedunculated polyps of 10 mm or more in size
• Type 1 or 2 according to NBI International Colorectal Endoscopy (NICE) classification
• Patients must sign an informed consent form prior to registration in study

Exclusion Criteria:

• Lesions with signs of deep invasion (hard, friable tissue, poor mobility, positive "non-lifting" sign)
• Type 3 according to NICE classification
• Colorectal cancer
• Patients with unstable chronic disease (melitus diabetes, hypertension, heart failure, kidney failure, liver failure, chronic obstructive pulmonary disease)
• Hemostasis disorder (INR > 1.5; platelets < 100000/mm3)