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  • Matthew Rutter
    University Hospital of North Tees
  • Rachel Evans
  • Zoe Hoare
  • Christian von Wagner
    University College London
  • Jill Deane
    University Hospital of North Tees
  • Shiran Esmally
    University Hospital of North Tees
  • Tony Larkin
  • Rhiannon Tudor Edwards
  • Seow Tien Yeo
  • Llinos Spencer
  • Emily Holmes
  • Brian Saunders
    St Mark's Hospital
  • Colin Rees
    South Tyneside NHS Foundation Trust
  • Zacharias Tsiamoulos
    St Mark's Hospital
  • Iosif Beintaris
    University Hospital of North Tees
Objectives The English Bowel Cancer Screening Programme invites 55 year olds for a sigmoidoscopy (Bowel Scope Screening (BSS)), aiming to resect premalignant polyps, thus reducing cancer incidence. A national patient survey indicated higher procedural pain than anticipated, potentially impacting on screening compliance and effectiveness. We aimed to assess whether water-assisted sigmoidoscopy (WAS), as opposed to standard CO2 technique, improved procedural pain and detection of adenomatous polyps.
Design The WASh (Water-Assisted Sigmoidoscopy) trial was a multicentre, single-blind, randomised control trial for people undergoing BSS. Participants were randomised to either receive WAS or CO2 from five sites across England. The primary outcome measure was patient-reported moderate/severe pain, as assessed by patients on a standard Likert scale post procedure prior to discharge. The key secondary outcome was adenoma detection rate (ADR). The costs of each technique were also measured.

Results 1123 participants (50% women, mean age 55) were randomised (561 WAS, 562 CO2). We found no difference in patient-reported moderate/severe pain between WAS and CO2 (14% in WAS, 15% in CO2; p=0.47). ADR was 15% in the CO2 arm and 11% in the WAS arm (p=0.03); however, it remained above the minimum national performance standard in both arms. There was no statistical difference in mean number of adenomas nor overall polyp detection rate. There was negligible cost difference between the two techniques.
Conclusion In the context of enema-prepared unsedated screening sigmoidoscopies performed by screening-accredited endoscopists, no difference in patient-reported pain was seen when using either a CO2 or WAS intubation technique.
Trial registration number ISRCTN81466870.
Original languageEnglish
Pages (from-to)845–852
Number of pages8
Issue number5
Early online date7 Sept 2020
Publication statusPublished - 7 Apr 2021

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