Multicenter Evaluation of Right Colon Polyp Miss Rates Using Water Exchange Versus CO2 Insufflation
Condition: Right Colon Adenoma Miss Rate; Right Colon Hyperplastic Polyp Miss Rate
MeSH terms: Adenoma; Polyps; Hyperplasia
Study type: Interventional

Summary: 
      A prospective multicenter randomized controlled trial (RCT) comparing water exchange (WE)
      colonoscopy and carbon dioxide (CO2) insufflation in terms of right colon combined adenoma
      miss rate (AMR) and hyperplastic polyp miss rate (HPMR) by tandem inspection.
    

Detailed description: 
      This will be a prospective RCT comparing CO2 insufflation and WE in terms of right colon
      combined AMR and HPMR by tandem inspection. It will be a multicenter study conducted in three
      community hospitals (Evergreen General Hospital, Taoyuan; Dalin Tzu-Chi Hospital, Chiayi;
      Taipei Medical University Hospital, Taipei) in Taiwan. Consecutive patients aged 45 years or
      older undergoing colonoscopy for screening, surveillance, and positive FIT will be considered
      for enrollment from December 2019 to May 2021. A written informed consent will be obtained
      from all participating patients. Participants will be randomized in a 1:1 ratio to undergo
      either the CO2 insufflation colonoscopy (CO2 group) or WE colonoscopy (WE group). WE
      colonoscopies will be performed by five board-certified colonoscopists (Chi-Liang Cheng,
      Yen-Lin Kuo [Evergreen General Hospital]; Yu-Hsi Hsieh, Chih-Wei Tseng [Dalin Tzu-Chi
      Hospital]; Jui-Hsiang Tang [Taipei Medical University Hospital]. Standard colonoscopes
      (CF-Q260AL/I, CF-HQ290L/I; Olympus Medical Systems Corp., Tokyo, Japan) will be used. Felix
      W. Leung will be involved in the study design, data analyses, and report preparation, but not
      in patient enrollment. Antispasmodic medication will not be administered during colonoscopy
      examination. CO2 insufflation will be used for CO2 group and the withdrawal phase of the WE
      group. In the WE group, the air pump will be turned off before starting the procedure. During
      the insertion phase, air and residual water or feces in the rectum will be aspirated, and
      then the colon will be irrigated with warm water. When the cecum is reached and after most of
      the water is suctioned to collapse the cecal lumen, CO2 will be opened. In the CO2 group,
      colonoscopy is performed in the usual fashion, with minimal insufflation required to aid
      insertion. Cleaning in the CO2 group will be performed entirely during withdrawal. Upon
      arriving at the cecum, CO2 insufflation will be used in both groups and the scope will be
      withdrawn from the cecum to the hepatic flexure, with inspection of the mucosa at the same
      time. All polyps identified will be resected and sent for pathology evaluation. The most
      distal part of the hepatic flexure will be marked by a forceps biopsy and then the scope will
      be reinserted into the cecum by the first endoscopist using CO2 insufflation. A tandem
      inspection of the right colon will then be performed by a blinded endoscopist in both study
      groups. All polyps found herein will be counted as the missed polyps. After the second
      withdrawal to the mark of distal hepatic flexure, the remainder of the colon will be examined
      in a standard manner by the first endoscopist. Polyp search and resection will be performed
      during the withdrawal phase in both groups. Insertion polypectomy will not be performed.
    

Intervention name(s): Colon Polypectomy
Intervention type(s): Procedure
Intervention description(s): Polyp search and resection will be performed entirely during the withdrawal phase in both WE and CO2 groups. Insertion inspection and polypectomy will not be performed. All polyps in the proximal colon, defined as cecum, ascending colon, hepatic flexure, and transverse colon, will be removed irrespective of their size and appearance.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment