Changes

April 2024 — reviewed. A literature search was conducted in March 2024 to identify evidence-based guidelines, UK policy, systematic reviews, and key RCTs published since the last revision of this topic. No major changes to clinical recommendations have been made.

Update

Goals

To support primary healthcare professionals to:

• Provide information on the NHS bowel screening programme, including the rationale, risks and benefits, and what to expect.
• Raise awareness of bowel screening and promote uptake.

Outcome measures

Audit criteria

QOF indicators

QIPP - Options for local implementation

NICE quality standards

Why screen for bowel cancer?

• Bowel cancer is the fourth most common cancer in the UK.
  • In the UK between 2016 and 2018, 42,886 new cases were diagnosed per year [CRUK, 2024]:
    • 35,496 in England — age-standardised incidence rate 68.5 per 100,000.
    • 3,884 in Scotland — age-standardised incidence rate 73.7 per 100,000.
    • 2,325  in Wales — age-standardised incidence rate 72.0 per 100,000.
    • 1,181 in Northern Ireland — age-standardised incidence rate 73.6 per 100,000.
    • 55% of cases were male and 45% female.
  • Between 2017 and 2019 there were 16,800 deaths from bowel cancer each year in the UK — it is the second most common cause of cancer death in the UK [UKNSC, 2018; CRUK, 2024].
  • The risk of developing bowel cancer increases with age.
    • Around 80% of people diagnosed with bowel cancer are over 60 years of age [UKNSC, 2018].
• The NHS Bowel Cancer Screening Program was introduced in 2006 with the aim of identifying bowel cancer at an early stage when treatment is more likely to be successful.
  • The 5-year survival rate following diagnosis of bowel cancer is 61.5% in the least deprived group and 52.6% in the most deprived group — survival is strongly related to the stage at diagnosis [CRUK, 2024].
  • The 5-year survival rate can be improved from around 10% for a metastatic cancer at diagnosis to around 90% for bowel cancer detected early at Dukes’ stage A [UKNSC, 2018; CRUK, 2024].
  • In addition to identifying cancers earlier, screening can also reduce the incidence of bowel cancer by endoscopic removal of pre-malignant lesions at colonoscopy.
• Regular bowel cancer screening has been shown to reduce the risk of dying from bowel cancer by over 16% [UKNSC, 2018].

What are the potential harms of screening?

Potential harms with bowel screening include:

• False-positive faecal blood test results
  • May cause anxiety and lead to unnecessary further investigations such as colonoscopy.
• False-negative results
  • Screening tests are not 100% effective, some bowel cancers may be missed.
  • One meta-analysis (n=29 studies) looking at the incidence of faecal occult blood test interval cancers in population-based bowel cancer screening found that pooled incidence rates of interval bowel cancer following FIT and gFOBT were 20 (95% CI 14–29) and 34 (95% CI 20–57) per 100,000 person-years, respectively. In the studies that included FIT results (n=17), the median faecal haemoglobin positivity cut-off used was 20 (range 10–200) µg Hb/g faeces [Wieten, 2019].
• Overdiagnosis
  • Some people may be treated for lesions that would not have caused any harm.
• Risks of colonoscopy
  • Colonoscopy is associated with a small risk of complications (such as bleeding or perforation), which is increased by interventions such as polypectomy.
  • A systematic review and meta-analysis (n=60 studies) looking at morbidity and mortality associated with colorectal cancer screening found that colonoscopy in asymptomatic patients was associated with major bleeding in 0.8/1000 procedures (95% CI 0.18–1.63) and perforation in 0.07/1000 procedures (95% CI 0.006–0.17). The authors found that literature on harms other than perforation and bleeding was limited [Vermeer, 2017].

[Lin, 2021; CRUK, 2022]

Which screening test is used in the NHS bowel screening programme?

• The presence of blood in stools is an indicator of pre-malignant and malignant bowel lesions. As blood in stools may not be visible, faecal occult blood testing is used as a primary screening tool to detect its presence.
  • Colonoscopy (the definitive diagnostic investigation for bowel cancer) is unsuitable as a primary screening test because it is:
    • Associated with a small but significant risk of complications (such as perforation) and mortality.
    • Requires specially trained clinical staff to carry it out.
    • Invasive and therefore unlikely to be acceptable to the population.
• The test used in the NHS bowel cancer screening programme is faecal immunochemical testing (FIT). 

  [UKNSC, 2018; PHE, 2021; CRUK, 2022; PHS, 2022]

What are the outcomes of screening?

• For faecal immunochemical testing (FIT), people with:
• • A normal test will be returned to routine recall (every 2 years up to the age of 75 years).
  • An abnormal test (above or at the FIT threshold) will be assessed by a specialist nurse and offered colonoscopy or imaging (such as CT colonography) if unsuitable for colonoscopy.
  • A spoilt kit (for example out of date or due to a technical fault) will be sent a repeat test kit.
• At colonoscopy, people who are found to have:
  • No abnormalities will be returned to routine recall (every 2 years up to the age of 75 years).
  • Low-risk adenoma (1 or 2 small [less than 1 cm] adenomas) will be returned to routine recall.
  • Intermediate-risk adenoma (3 or 4 adenomas, or, at least 1 adenoma at least 1 cm in size) or high-risk adenoma (5 or more adenomas, or 3 or more adenomas of which at least 1 is greater than or equal to 1 cm) will be invited for colonoscopic surveillance/reviewed by the multidisciplinary team.
  • Cancer will be referred to the multidisciplinary team for treatment and follow up.
  • Other pathology (such as Crohn's disease, ulcerative colitis, or diverticulosis) will be referred to an appropriate specialist, treated, or advised.
• If the person does not respond to the bowel cancer screening invitation:
  • A reminder letter is sent at 4–6 weeks. 
  • If there is no response at 3 months, the person's GP receives an electronic notification of this.
  • Non-responders are re-invited at the next round of screening (2 year intervals).

  [PHW, 2021; PHS, 2022; Bowel Cancer UK, 2024]

What is the NHS bowel screening programme in the UK?

• Recommendations on population screening are made by the UK National Screening Committee (UK NSC) to ministers in the four UK countries.
  • In 2016 the UK NSC recommended that faecal immunochemical testing (FIT) should replace guaiac faecal occult blood testing (gFOBt) as the primary test for bowel cancer screening.
    • FIT replaced gFOBt in Scotland in 2017 — for more information, see the section on the NHS bowel cancer screening programme in Scotland.
    • FIT was introduced as the primary screening test in England and Wales in 2019  — for more information, see the sections on the NHS bowel cancer screening programme in England and the NHS bowel cancer screening programme in Wales.
    • FIT was introduced to the screening programme in Northern Ireland in 2021 — for more information, see the section on the NHS bowel cancer screening programme in Northern Ireland.

[UKNSC, 2018; PHE, 2021]

The NHS Bowel Cancer Screening Programme is not intended to replace other methods of screening for people known to be at high risk for bowel cancer.

• There are separate guidelines for colorectal cancer screening in high-risk groups, including people with:
  • A previous diagnosis of colorectal cancer.
  • Colonic adenomas.
  • Ulcerative colitis or Crohn's disease.
  • Acromegaly.
  • A family history of hereditary non-polyposis colorectal cancer, familial adenomatous polyposis, or Peutz-Jeghers syndrome.
  • A strong family history of bowel cancer, indicated by two first-degree relatives with colorectal cancer or one first-degree relative with colorectal cancer when younger than 45 years of age.

[NICE, 2022] 

Scenario: Bowel screening

From age 50 years onwards.

Search strategy

Scope of search

A literature search was conducted for guidelines and systematic reviews on primary care management of colorectal screening.

Search dates

April 2019 - February 2024

Key search terms

The terms listed below are the core search terms that were used for EBSCOhost MEDLINE (searched 18th April 2019). These were combined with filters to identify guidelines, systematic reviews and primary care relevant literature in EBSCOhost MEDLINE. The strategy was adapted for The Cochrane Library databases. 

S7    S5 OR S6 
S6    TI (colorectal OR bowel) N3 screen* 
S5    S3 AND S4 
S4    (MH "Colorectal Neoplasms+") 
S3    S1 OR S2 
S2    (MH "Early Detection of Cancer") 
S1    (MH "Mass Screening+")

Sources of guidelines

• National Institute for Health and Care Excellence (NICE)
• Scottish Intercollegiate Guidelines Network (SIGN)
• Royal College of Physicians
• Royal College of General Practitioners
• Royal College of Nursing
• NICE Evidence
• World Health Organization
• Guidelines International Network
• TRIP database
• Agency for Healthcare Research and Quality
• Institute for Clinical Systems Improvement
• National Health and Medical Research Council (Australia)
• Royal Australian College of General Practitioners
• British Columbia Medical Association
• Canadian Medical Association
• Alberta Medical Association
• Michigan Quality Improvement Consortium
• Singapore Ministry of Health
• National Resource for Infection Control
• RefHELP NHS Lothian Referral Guidelines
• Medline (with guideline filter)
• Driver and Vehicle Licensing Agency
• NHS Health at Work (occupational health practice)

Sources of systematic reviews and meta-analyses

• The Cochrane Library:
  • Systematic reviews
  • Protocols
  • Database of Abstracts of Reviews of Effects
• Medline (with systematic review filter)
• EMBASE (with systematic review filter)

Sources of health technology assessments and economic appraisals

• NIHR Health Technology Assessment programme
• The Cochrane Library:
  • NHS Economic Evaluations
  • Health Technology Assessments
• Canadian Agency for Drugs and Technologies in Health
• International Network of Agencies for Health Technology Assessment

Sources of randomized controlled trials

• The Cochrane Library:
  • Central Register of Controlled Trials
• Medline (with randomized controlled trial filter)
• EMBASE (with randomized controlled trial filter)

Sources of evidence based reviews and evidence summaries

• Bandolier
• Drug and Therapeutics Bulletin
• TRIP database
• Central Services Agency COMPASS Therapeutic Notes

Sources of national policy

• Department of Health
• Health Management Information Consortium (HMIC)

Patient experiences

• Healthtalk
• BMJ - Patient Journeys

Sources of medicines information

The following sources are used by CKS pharmacists and are not necessarily searched by CKS information specialists for all topics. Some of these resources are not freely available and require subscriptions to access content.

• British National Formulary (BNF)
• electronic Medicines Compendium (eMC)
• European Medicines Agency (EMEA)
• LactMed
• Medicines and Healthcare products Regulatory Agency (MHRA)
• REPROTOX
• Scottish Medicines Consortium
• Stockley's Drug Interactions
• TERIS
• TOXBASE
• Micromedex
• UK Medicines Information

Stakeholder engagement

Our policy

The external review process is an essential part of CKS topic development. Consultation with a wide range of stakeholders provides quality assurance of the topic in terms of:

• Clinical accuracy.
• Consistency with other providers of clinical knowledge for primary care.
• Accuracy of implementation of national guidance (in particular NICE guidelines).
• Usability.

Principles of the consultation process

• The process is inclusive and any individual may participate.
• To participate, an individual must declare whether they have any competing interests or not. If they do not declare whether or not they have competing interests, their comments will not be considered.
• Comments received after the deadline will be considered, but they may not be acted upon before the clinical topic is issued onto the website.
• Comments are accepted in any format that is convenient to the reviewer, although an electronic format is encouraged.
• External reviewers are not paid for commenting on the draft topics.
• Discussion with an individual or an organization about the CKS response to their comments is only undertaken in exceptional circumstances (at the discretion of the Clinical Editor or Editorial Steering Group).
• All reviewers are thanked and offered a letter acknowledging their contribution for the purposes of appraisal/revalidation.
• All reviewers are invited to be acknowledged on the website. All reviewers are given the opportunity to feedback about the external review process, enabling improvements to be made where appropriate.

Stakeholders

• Key stakeholders identified by the CKS team are invited to comment on draft CKS topics. Individuals and organizations can also register an interest to feedback on a specific topic, or topics in a particular clinical area, through the Getting involved section of the Clarity Informatics website.
• Stakeholders identified from the following groups are invited to review draft topics:
  • Experts in the topic area.
  • Professional organizations and societies (for example, Royal Colleges).
  • Patient organizations, Clarity has established close links with groups such as Age UK and the Alzheimer’s Society specifically for their input into new topic development, review of current topic content and advice on relevant areas of expert knowledge.
  • Guideline development groups where the topic is an implementation of a guideline.
  • The British National Formulary team.
  • The editorial team that develop MeReC Publications.
• Reviewers are provided with clear instructions about what to review, what comments are particularly helpful, how to submit comments, and declaring interests.

Patient engagement

Clarity Informatics has enlisted the support and involvement of patients and lay persons at all stages in the process of creating the content which include:

• Topic selection
• Scoping of topic
• Selection of clinical scenarios
• First draft internal review
• Second draft internal review
• External review
• Final draft and pre-publication

Our lay and patient involvement includes membership on the editorial steering group, contacting expert patient groups, organizations and individuals.

Evidence exclusion criteria

Our policy

Scoping a literature search, and reviewing the evidence for CKS is a methodical and systematic process that is carried out by the lead clinical author for each topic. Relevant evidence is gathered in order that the clinical author can make fully informed decisions and recommendations. It is important to note that some evidence may be excluded for a variety of reasons. These reasons may be applied across all CKS topics or may be specific to a given topic.

Studies identified during literature searches are reviewed to identify the most appropriate information to author a CKS topic, ensuring any recommendations are based on the best evidence. We use the principles of the GRADE and PICOT approaches to assess the quality of published research. We use the principles of AGREE II to assess the quality of published guidelines.

Standard exclusions for scoping literature:

• Animal studies
• Original research is not written in English

Possible exclusions for reviewed literature:

• Sample size too small or study underpowered
• Bias evident or promotional literature
• Population not relevant
• Intervention/treatment not relevant
• Outcomes not relevant
• Outcomes have no clear evidence of clinical effectiveness
• Setting not relevant
• Not relevant to UK
• Incorrect study type
• Review article
• Duplicate reference

Organizational, behavioural and financial barriers

Our policy

The CKS literature searches take into consideration the following concepts, which are discussed at the initial scoping of the topic.

• Feasibility
  • Studies are selected depending on whether the intervention under investigation is available in the NHS and can be practically and safely undertaken in primary care.
• Organizational and Financial Impact Analysis
• Studies are selected and evaluated on whether the intervention under investigations may have an impact on local clinical service provision or national impact on cost for the NHS. The principles of clinical budget impact analysis are adhered to, evaluated and recorded by the author. The following factors are considered when making this assessment and analysis.
  • Eligible population
  • Current interventions
  • Likely uptake of new intervention or recommendation
  • Cost of the current or new intervention mix
  • Impact on other costs
  • Condition-related costs
  • In-direct costs and service impacts
  • Time dependencies
• Cost-effectiveness or cost-benefit analysis studies are identified where available. 

We also evaluate and include evidence from NICE accredited sources which provide economic evaluations of recommendations, such as NICE guidelines. When a recommended action may not be possible because of resource constraints, this is explicitly indicated to healthcare professionals by the wording of the CKS recommendation.

Declarations of interest

Our policy

Clarity Informatics requests that all those involved in the writing and reviewing of topics, and those involved in the external review process to declare any competing interests. Signed copies are securely held by Clarity Informatics and are available on request with the permission of the individual. A copy of the declaration of interest form which participants are asked to complete annually is also available on request. A brief outline of the declarations of interest policy is described here and full details of the policy is available on the Clarity Informatics website. Declarations of interests of the authors are not routinely published, however competing interests of all those involved in the topic update or development are listed below. Competing interests include:

• Personal financial interests
• Personal family interest
• Personal non-financial interest
• Non-personal financial gain or benefit

Although particular attention is given to interests that could result in financial gains or losses for the individual, competing interests may also arise from academic competition or for political, personal, religious, and reputational reasons. An individual is not obliged to seek out knowledge of work done for, or on behalf of, the healthcare industry within the departments for which they are responsible if they would not normally expect to be informed.

Who should declare competing interests?

Any individual (or organization) involved in developing, reviewing, or commenting on clinical content, particularly the recommendations should declare competing interests. This includes the authoring team members, expert advisers, external reviewers of draft topics, individuals providing feedback on published topics, and Editorial Steering Group members. Declarations of interest are completed annually for authoring team and editorial steering group members, and are completed at the start of the topic update and development process for external stakeholders.

Competing interests declared for this topic:

None.