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 March 2027. 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 had funding to continue to collect follow-up information on cancers and deaths for the UKFSST until March 2017. We have now been awarded additional funding to continue to follow-up the UKFSST cohort for a further 10 years to March 2027, until all the participants have reached the age of 80 years. 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 March 2037.
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 (also known as bowel-scope) 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 (bowel-scope) 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.
In addition to the original study objectives, the UKFSST study team has identified the following potential questions which could be addressed by further analysis of the UKFSST dataset. These analyses will be conducted by the CSPRG medical statisticians and published in peer reviewed journals. No additional data will be requested to meet these objectives.
- Does the quality of flexible sigmoidoscopy screening affect the future risk of getting bowel cancer and dying from this disease?
- Does patient experience and procedural factors affect the performance of flexible sigmoidoscopy screening?
- How safe and acceptable is a once-only flexible sigmoidoscopy?
- How does having a family history of bowel cancer effect the risk of developing this disease after screening?
- Can the severity of disease at diagnosis be used to determine the risk of dying from bowel cancer?
- Among patients identified as higher-risk at their flexible sigmoidoscopy screening, how effective is repeated colonoscopy (examination of the entire bowel) at routine intervals?
- How commonly does bowel cancer in the upper part of the bowel develop after flexible sigmoidoscopy, and can this be predicted by the number and type of polyp detected at flexible sigmoidoscopy?
- Does smoking history affect the risk of developing polyps and bowel cancer?
- Can various medications affect the risk of developing polyps and bowel cancer?
- Among patients taking part in the UKFSST and also invited to take part in the National Bowel Cancer Screening Programme (BCSP), for which they complete Faecal Occult Blood Tests (FOBTs), how do these two screening tests affect the risk of getting bowel cancer?
- Can prior flexible sigmoidoscopy affect participation and outcomes of FOBTs in the BCSP?
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