UK Flexible Sigmoidoscopy Screening Trial
The UK Flexible Sigmoidoscopy Screening Trial (UKFSST) started in 1994 and is still on-going. The trial has received funding from a number of government and charitable sources including: the UK Medical Research Council, the NHS National Institute for Health Research Efficacy and Mechanism Evaluation programme, Cancer Research UK, and KeyMed Ltd. The UKFSST is a major research study and recruited over 170,000 people from across the UK. The first results assessing the effectiveness of the screening tested in this trial were published in 2010. The results confirmed that the test was very effective at preventing bowel cancer and very long-lasting. This study led directly to the introduction of flexible sigmoidoscopy (bowel scope/Flexi-scope) screening in the NHS English Bowel Cancer Screening Programme.
Harpal Kumar, Chief Executive of Cancer Research UK said of the UKFSST:
“Cancer Research UK does not often use the word ‘breakthrough’ but this is one of those rare occasions when I am going to. It is extremely rare to see the results of a clinical trial which are quite as compelling as this. Flexi-scope needs to be brought in as soon as possible. Every week of delay will risk scores of lives.”
What were the aims of the UKFSST?
The trial aimed to determine whether having a once-only flexible sigmoidoscopy screening test at around age 60 years was effective at preventing bowel cancer and could reduce the number of deaths from this disease. The trial also aimed to determine how long the benefit of the test lasted and the best age for it to be done.
What type of study was the UKFSST?
The UKFSST was a randomised-controlled trial. People who participated in the trial were assigned randomly to receive either flexible sigmoidoscopy screening or the usual care that was offered at the time of the trial, which was no screening. Well-designed randomised controlled studies, such as the UKFSST, are considered to provide the best evidence for whether a new treatment works effectively.
What is the flexible sigmoidoscopy (bowel scope, Flexi-scope) test?
During flexible sigmidoscopy (also called ‘bowel scope’ or Flexi-scope), a narrow, flexible tube with a camera on the end is inserted into the rectum and up into the lower part of the large bowel by a specialist nurse or doctor. Flexible sigmoidoscopy is used to examine the inner surface of the lower bowel for growths, called polyps or adenomas. Polyps are common and are not cancerous, but some can develop into cancer so they are generally removed as part of the procedure, or during a follow up test.
When and where did the study take place?
The UKFSST study recruited people from 506 participating GP practices based in 14 UK centres: 11 in England, two in Wales, and one in Scotland. Recruitment and screening started in November 1994 and were completed in March 1999.
The map below shows the geographical locations of the 14 UK centres that took part in the UKFSST study.
Who is included in the study?
375,744 men and women who were assessed for eligibility for the UKFSST trial included:
- were registered at a participating GP practice between November 1994 and March 1999; and
- were aged 55–64 years between November 1994 and March 1999
Of these, 170,432 people indicated in the study questionnaire or letter sent between September 1994 and March 1999 that they would take up the offer of screening if invited; and were assessed as being eligible for the study; and were randomised. 40,674 of these 170,432 people were screened.
The remaining 205,312 men and women included those who were sent a study questionnaire or letter between September 1994 and March 1999 asking whether they would take up the offer of screening if invited and
- indicated that they would take up the offer of screening if invited and were eligible for the study but were not randomised as 40,000 people had already been screened (funding was given to screen 40,000 people); or
- indicated that they would take up the offer of screening if invited, but were subsequently assessed as not eligible for the study; or
- did not respond to the study questionnaire or letter; or
- responded to the study questionnaire or letter that they would not take up the offer of screening if invited.
What type of information does the CSPRG hold for the purposes of the UKFSST?
The CSPRG holds the following personal information for the purposes of the UKFSST, which covers:
- patient demographics – name, address, date of birth, NHS number, GP for all individuals in the age range 55-64 years between November 1994 and March 1999 belonging to participating general practices;
- questionnaire data – including responses to various questionnaires sent at different stages of the study, family history of bowel cancer, symptoms, previous examinations and diet and smoking consumption (for selected groups);
- clinical information – including medical data collected prior to screening, details of symptoms, results of any medical tests or procedures and blood samples (for selected groups);
- cancer diagnoses (for randomised patients) including histological diagnosis and stage of the disease;
- death data for all individuals in the age range 55-64 years between November 1994 and March 1999 belonging to participating general practices.
We require the information that we hold in order to answer our research questions and to guarantee the quality and integrity of our results. It will not be possible to identify individuals from the published results of this study.
We have not finished collecting the cancer and death data we need and will continue to do so until at least December 2016. Our Patient Data section provides further details on what information we hold for the purposes of our research, and how we use and protect this information.
What approvals has this study received?
Everyone who received a flexible sigmoidoscopy as part of the UKFSST gave their consent for this procedure (40,674 people).
Consent was not sought from people who received no further contact other than the initial questionnaire as the group in question was extremely large (335,070 people) and it was not possible to ask for consent from each individual. We received permission to conduct this research study from the independent ethical review committees and organisations responsible for the data of NHS patients, including:
- local research ethics committees in each of the 14 centres and the South-East multicentre research ethics committee;
- Section 251 approval from the Patient Information Advisory Group (PIAG – a predecessor of both the National Information Governance Board/NIGB and the Confidentiality Advisory Group) in England, and an equivalent panel in Scotland, the Privacy Advisory Committee (PAC) of National Services Scotland (NSS);
- Research and Development approval from the NHS Trusts managing the centres involved in the trial;
- approval from the Caldicott Guardian of the North West London NHS Trust;
- approval from the UK Cancer Registries, NHS Digital (previously the Health & Social Care Information Centre), NHS Central Register (NHSCR), and the Office for National Statistics (ONS).
Why do we need to hold identifiable data for this study?
We need identifiable data to enable our data providers (such as NHS Digital, NHSCR, NSS, ONS, Cancer Registries and hospitals) to identify the study participants and provide us with follow-up data on cancers/deaths.
How long will we retain the data?
We currently have funding to continue to collect follow-up information on cancers and deaths for the UKFSST until 31st December 2016. Imperial College London, the organisation responsible for this study, requires that we hold data from all clinical studies for 10 years after the study end date. We therefore currently plan to hold the data for this study until December 2026. We plan to apply for an extension to continue to follow-up the UKFSST cohort for a further 10 years until all the patients on our cohort have reached the age of 80 years.
What were the results of the study and what impact have they had?
When the first results of the UKFSST were analysed in 2010, they showed that people who were screened just once with flexible sigmoidoscopy were:
- less likely to get bowel cancer – it prevented about one in three new cases of bowel cancer;
- less likely to die from the disease – it prevented four in every 10 deaths from bowel cancer.
The protective effects of the once-only flexible sigmoidoscopy also appeared to be long lasting. The UKFSST results were published in The Lancet in 2010.
Because the UKFSST demonstrated that flexible sigmoidoscopy screening can prevent bowel cancer from developing, this suggested that offering a once-only flexible sigmoidoscopy screening test to people in the UK should reduce the numbers of people getting bowel cancer and dying from this disease. In 2010, the UK government announced a £60 million investment to introduce bowel scope screening as part of the English NHS Bowel Cancer Screening Programme. Roll-out of bowel scope screening began in 2013 and is expected to cover the entire population by 2018. It has been estimated that bowel scope screening could prevent up to 5,000 people from getting bowel cancer and up to 3,000 deaths from the disease in the UK each year. It is hoped that cancer of the rectum, the lowest part of the bowel examined, could one day become a rare disease.
The results of a further 7 years of follow-up were published in The Lancet in Feb 2017 and show that a single flexible sigmoidoscopy continues to provide substantial protection from bowel cancer diagnosis and death, with protection lasting at least 17 years. Cancer Research UK and Imperial College London also published news articles.
Atkin W, Wooldrage K, Parkin DM, et al. Long term effects of once-only flexible sigmoidoscopy screening after 17 years of follow-up: the UK Flexible Sigmoidoscopy Screening randomised controlled trial. Lancet. 2017 Apr 1; 389 (10076): 1299-1311.
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Atkin WS, Edwards R, Kralj-Hans I, et al. Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial. Lancet. 2010; 375: 1624–33.
Austin KL, Power E, Solarin I, et al. Perceived barriers to flexible sigmoidoscopy screening for colorectal cancer among UK ethnic minority groups: a qualitative study. J Med Screen 2009; 16: 174–179.
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Robb KA, Power E, Atkin W, et al. Ethnic differences in participation in flexible sigmoidoscopy screening in the UK. J Med Screen 2008; 15: 130-136.
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Thomas-Gibson S, Rogers, PA, Cooper S, et al. Judgement of quality of bowel preparation at screening flexible sigmoidoscopy is associated with variability in adenoma detection rates. Endoscopy. 2006;38:456-60.
Gunter MJ, Watson MA, Loktionov AS, et al. No association between cytochrome P450 and Glutathione S-Transferase gene polymorphisms and risk of colorectal adenoma: results from the UK flexible sigmoidoscopy screening trial. Cancer Epidemiology Biomarkers Prev. 2005;14(4):1028-30.
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Martin JP, Sexton BF, Saunders BP, et al. Inhaled patient-administered nitrous oxide/oxygen mixture does not impair driving ability when used as analgesia during screening flexible sigmoidoscopy. Gastrointest Endosc. 2000;51:701-3.
Taylor T, Williamson S, Wardle J, et al. Acceptability of flexible sigmoidoscopy screening in older adults in the UK. J Med Screen. 2000;7:38-45.
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Frew E, Wolstenholme JL, Atkin WS, et al. Estimating time and travel costs incurred in clinic-based screening: flexible sigmoidoscopy screening for colorectal cancer. J Med Screen. 1999;6:119-23.
Wardle J, Taylor T, Sutton S, et al. Does publicity about cancer screening raise fear of cancer? Randomised trial of the psychological effect of information about cancer screening. Br Med J. 1999;319:1037-8.
Hart AR, Kudo S, Mackay EH, et al. Flat adenomas exist in asymptomatic people: important implications for colorectal cancer screening programmes. Gut. 1998;43:229-31.
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