Right Colon Polyp Miss Rates of Water Exchange and Carbon Dioxide Insufflation Colonoscopy
Condition: Right Colon Adenoma Miss Rate; Right Colon Hyperplastic Polyp Miss Rate
MeSH terms: Adenoma; Polyps; Hyperplasia
Study type: Interventional

Summary: 
      This will be a prospective randomized controlled trial comparing CO2 insufflation and WE in
      terms of right colon combined adenoma miss rate (AMR) and hyperplastic polyp miss rate (HPMR)
      by tandem inspection. It will be a single-site study conducted in Taiwan.
    

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 is originally designed as a multicenter study
      conducted in three community hospitals in Taiwan. Consecutive patients will be enrolled from
      April 2019 to October 2020. A written informed consent will be obtained from all
      participating patients. The study has obtained ethical approval from the Joint Institutional
      Review Board of Taiwan (19-002-T-1) and has been registered with ClinicalTrials.gov
      (NCT03845933). Due to delay in obtaining IRB approval in two of the participating hospitals
      (Dalin Tzu-Chi Hospital obtained IRB approval in late May 2019 and has not recruited any
      patient; Taipei Medical University Hospital has not obtained IRB approval in early June 2019)
      and rapid recruitment of Evergreen General Hospital since April 2019, which has recruited and
      completed more than 90 patients in the end of May 2019, we have amended the study design from
      multicenter study to single-center study and have obtained the approval of this amendment
      from the Joint Institutional Review Board of Taiwan. Consecutive patients aged 45 years or
      older undergoing colonoscopy for screening, surveillance, and positive FIT will be considered
      for enrollment from April 2019 to October 2020. Participants will be randomized in a 1:1
      ratio to undergo either the CO2 insufflation colonoscopy (CO2 group) or WE colonoscopy (WE
      group). Colonoscopies will be performed by two board-certified colonoscopists (Chi-Liang
      Cheng, Yen-Lin Kuo). Standard colonoscopes (CF-Q260AL/I; Olympus Medical Systems Corp.,
      Tokyo, Japan) will be used. All colonoscopists have performed more than 1000 conventional
      colonoscopies. Hands-on coaching by a WE expert (Felix W. Leung) to standardize the WE method
      has been completed. Each colonoscopist has completed 100 cases of WE learning curve. Felix W.
      Leung will be involved in the study design, data analyses, and report preparation, but not in
      patient enrollment. 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, 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 second
      endoscopist blinded to the insertion method 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 during the withdrawal phase in both groups. Insertion polypectomy will not be performed. All proximal colon polyps will be removed irrespective of their size and appearance.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment