Plain English Summary
Background and study aims
Bowel cancer is the fourth most commonly diagnosed cancer in the UK. Bowel cancers develop slowly from common bowel growths or polyps, so removing them can help prevent cancer. Screening with flexible sigmoidoscopy (also called ‘bowel scope’ or Flexi-scope) involves insertion of a thin flexible tube with a light and camera on the end into the bowel to examine the inner surface. Small bowel polyps can be removed during screening. The aim of the UK Flexible Sigmoidoscopy Screening Trial (UKFSST) was to determine whether having just one flexible sigmoidoscopy screen at around 60 years of age could prevent bowel cancer from developing and reduce the number of deaths from bowel cancer. The trial also aimed to determine how long any benefit lasts, and what is the best age to do the screening examination.
Who can participate?
Men and women who were aged 55–64 years and registered at a participating GP practice between November 1994 and March 1999.
What does the study involve?
The UKFSST was a randomised controlled trial. People who participated in the trial were randomly assigned to receive either flexible sigmoidoscopy screening or no screening (which was the usual care offered at the time of the trial).
What are the possible benefits and risks of participating?
Potential benefits of participating in the UKFSST included the possibility of being assigned to screening and having polyps detected and removed. Possible risks included adverse physical and psychological effects associated with the screening procedure and screening results. Individuals who participated in the trial but who were not assigned to screening received usual care and so were not worse off for having participated.
Where is the study run from?
The UKFSST recruited people from 506 GP practices that served 14 UK hospitals: 11 in England, two in Wales, and one in Scotland. Flexible sigmoidoscopy screening was done in endoscopy clinics at the hospitals.
When is the study starting and how long is it expected to run for?
Recruitment for the study and flexible sigmoidoscopy screening started in November 1994 and was completed in March 1999. The researchers have been following the participants since then, and will continue to follow them through 2024. The data will then be analysed and results written up, and the study will be completed by the 31st March 2027.
Who is funding the study?
National Institute for Health Research (NIHR) Health Technology Assessment (HTA) Programme (UK)
Who is the main contact?
Dr Amanda J Cross
Multicentre randomised trial of 'once only' flexible sigmoidoscopy screening for prevention of bowel cancer morbidity and mortality
1. To quantify the reduction in incidence and mortality
2. To determine the duration of efficacy of a single flexible sigmoidoscopy
3. To determine the optimum age for the examination
4. To evaluate health service research implications to permit an informed decision at the end of the trial about the suitability for implementation within a national screening programme
The criteria to be evaluated include:
1. Uptake, acceptability and impact
2. Quality control of the procedure
South East MREC, ref: MREC/03/1/002
Randomised controlled trial
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Not available in web format, please use the contact details to request a patient information sheet
'Once only' flexible sigmoidoscopy screening/control
Primary outcome measure
Incidence, mortality from colorectal cancer
Secondary outcome measures
Psychological morbidity, costs to the NHS
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
All 55-64 year old men and women from selected general practices
Target number of participants
Recruitment closed after randomising over 170,000 people
Participant exclusion criteria
1. If incapable of providing informed consent
2. Patients with a personal or family history of bowel cancer (greater than two family members)
3. A recent sigmoidoscopy or colonoscopy
4. Severe illness or life expectancy of less than 5 years
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Imperial College London
Medical Research Council (MRC) (UK)
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Publications of secondary endpoint analyses and further follow-up of the cohort are planned in high-impact peer reviewed journals between 2019 and 2028.
IPD sharing statement
The datasets generated during and/or analysed during the current study are not expected to be made available due to the terms and conditions of the data sharing agreements the researchers hold with third party data providers and their section 251 approval. However, anonymised, aggregated data may be made available upon application to the CSPRG: https://www.csprg.org.uk/patient-data/ and https://www.csprg.org.uk/contact-us/.
Intention to publish date
Participant level data
Not expected to be available
Basic results (scientific)
See additional file ISRCTN28352761_BasicResults_15Mar19.pdf
2002 baseline results in: https://www.ncbi.nlm.nih.gov/pubmed/11965274
2003 results in: https://www.ncbi.nlm.nih.gov/pubmed/12862195
2010 results in: https://www.ncbi.nlm.nih.gov/pubmed/20430429
2017 results in: https://www.ncbi.nlm.nih.gov/pubmed/28236467
2018 results in: https://www.ncbi.nlm.nih.gov/pubmed/30282520
2018 results in: https://www.ncbi.nlm.nih.gov/pubmed/29935150
- ISRCTN28352761_BasicResults_15Mar19.pdf Uploaded 26/03/2019