Randomised controlled trial of contrast-enhanced colonoscopy in the reduction of right-sided bowel cancer

Plain English Summary

Background and study aims
The UK Bowel Cancer Screening Programme has reduced the risk of death from bowel cancer by 15%. People testing positive on a bowel cancer screening stool test are offered colonoscopy (bowel camera examination) through the UK Bowel Cancer Screening Programme. About half of those have cancers or polyps (small abnormal growths that might lead to cancer in the future) found on colonoscopy. There is some evidence to suggest that these cancers could be caused by a certain type of flat polyp called a serrated polyp which can be difficult to detect during standard colonoscopy. Small studies have suggested that these polyps and may grow into cancer faster than the usual polyps and up to 1 in 5 bowel cancers may actually have developed from these subtle serrated polyps. Moreover, deaths from cancer of the upper bowel are not reducing.
This study will investigate if spraying a blue dye in the upper large bowel helps the doctor to detect more flat polyps during the colonoscopy. At the moment it is not known if spraying the dye in the upper large bowel is the best way to improve detection so participants who are due to have a screening colonoscopy will be randomly assigned into two groups; one to have a standard colonoscopy and the other to have a colonoscopy using the dye spray. This will allow a comparison of what happens between the two groups. The aim is to find out through this study if this method works in practice and improves the detection and removal of more serrated polyps within the screening programme.

Who can participate?
All participants in the UK bowel screening programmes (Wales, England, Scotland) who test positive on the FIT test (bowel cancer screening stool test) and are eligible for an index screening colonoscopy. Participants will only be ineligible for the study if they have received previous resectional colorectal surgery (as this would influence both study methods and outcomes depending on the length of residual colon in the individual), and/or have a known allergy to food colouring agent (as the Indigo Carmine dye is a safe food colouring agent but extremely rarely there may be individuals with a specific allergic response to this in the past).

What does the study involve?
Participants are randomly allocated into two groups; one to have a standard colonoscopy and the other to have a colonoscopy using the dye spray. They are followed up through routinely collected data systems.

A subset of participants may take part in the FORE AI substudy (https://www.isrctn.com/ISRCTN15467766).

What are the possible benefits and risks of participating?
By participating in bowel screening, all participants will already have taken steps to detect polyps and consequently reduce their risk for future bowel cancer. If allocated to the dye spray group, more polyps may be detected and removed that could have turned into cancer, which further minimises the risk of future bowel cancer. However, the colonoscopy with dye spray will take on average 6 minutes longer than usual, especially if extra polyps are found, and there may be an increased risk of complications (e.g. bleeding if polyps found are removed) although we believe this to be very unlikely. Additionally, there is the chance that the extra polyps remove may never have turned into cancer.
For all participants, the main benefits of the study will be to inform UK bowel cancer screening programmes in the future as to whether the using dye spray during colonoscopies helps in the detection of serrated polyps and possibly prevention of bowel cancers.
The blue dye used within the interventional arm is a safe food colouring agent and is already used routinely in various endoscopy procedures in standard clinical practice. Extremely rarely there may be individuals with a specific allergic response to this in the past. For this reason, anyone with a known allergy to a food colouring agent will be excluded from taking part in the study.

Where is the study run from?
The trial team are based in the Centre for Trials Research (CTR) at Cardiff University. Overall, the researchers plan that 25 centres in total across Wales, England and Scotland will participate in the recruitment for the trial. The lead centre will be Llandough Hospital (Cardiff & Vale University Health Board) as this is the site that the Chief Investigator, Dr Sunil Dolwani, is based at.

When is the study starting and how long is it expected to run for?
June 2019 to December 2025

Who is funding the study?
National Institute for Health Research (NIHR) (UK)

Who is the main contact?
Georgina Gardner
CONSCOP2@cardiff.ac.uk

Contact information

Study information

Eligibility

Locations

Countries of recruitment

• England
• Scotland
• United Kingdom
• Wales

Study participating centres

Sponsor information

Cardiff University
University/education

Research Governance Coordinator Research and Innovation Services Cardiff University
7th Floor, McKenzie House
30-36 Newport Rd
Cardiff
CF24 0DE
Wales
United Kingdom

Phone	+44 (0)29208 79130
Email	ShawC3@cardiff.ac.uk
Website	http://www.cardiff.ac.uk/
"ROR"	https://ror.org/03kk7td41

Funders

Funder type

Government

Results and Publications

Study outputs

Additional files

37714 CONSCOP2 protocol V4 17Nov2020.pdf

Editorial Notes

23/02/2024: Links to substudy registration were added.
22/02/2024: The following changes were made to the trial record:
1. A substudy (FORE AI) was mentioned in the study hypothesis, interventions, and plain English summary (this is registered separately [https://www.isrctn.com/ISRCTN15467766])
2. The total final enrolment was added.
3. The recruitment start date was changed from 01/05/2020 to 23/07/2021.
4. The recruitment end date was changed from 31/01/2023 to 09/02/2024.
5. The study participating centres Abertawe Bro Morgannwg University LHB, Aneurin Bevan University LHB, NHS Tayside, Royal Liverpool and Broadgreen University Hospitals NHS Trust, Powys Teaching LHB, Manchester University NHS Foundation Trust, Nhs Greater Glasgow and Clyde, St George's University Hospital, County Durham and Darlington NHS Trust were removed and John Radcliffe Hospital, Kettering General Hospital, Russells Hall Hospital, Bradford Royal Infirmary, Cheltenham General Hospital, Nottingham University Hospital, Sherwood Forest Hospitals NHS Foundation Trust, Royal Derby Hospital, Leeds Teaching Hospitals NHS Trust, University Hospital of North Durham were added.
17/01/2023: Uploaded protocol (not peer-reviewed) as an additional file.
13/12/2021: The recruitment end date was changed from 01/09/2022 to 31/01/2023.
28/07/2020: The ethics approval was added.
17/02/2020: Trial's existence confirmed by the NIHR.