Carbon dioxide insufflation

Gas insufflation is mandatory to ensure good visualisation during colonoscopy. Currently, air is commonly used for this purpose (Janssens et al. 2009). However, significant amounts of air can be retained in the GI tract (Bretthauer et al. 2003) causing pain and discomfort for the patient. Pain associated with colonoscopy has been identified as a major barrier to participation in CRC screening

Randomised trials have shown that carbon dioxide insufflation significantly reduces abdominal pain and discomfort in patients undergoing colonoscopy and flexible sigmoidoscopy (Bretthauer et al. 2002a; Bretthauer et al. 2002b; Sumanac et al. 2002; Church & Delaney 2003; Wong et al. 2008)

Side effects of C02 insufflation were not detected in unsedated patients in two randomised studies identified in the present literature search and involving 350 patients (Bretthauer et al. 2002b; Bretthauer et al. 2005). Slightly elevated end-tidal C02 levels were detected in sedated patients in the latter study, but only 52 sedated patients were included in the study and patients with chronic obstructive pulmonary disease, as well as patients with known C02 retention, were excluded.

Since carbon dioxide is an inert gas that cannot form a combustible mixture with hydrogen and methane, C02 insufflation will avoid the very rare risk of explosion during sigmoidoscopy or colonoscopy

Following incomplete colonoscopy, an alternative examination is frequently required. Provided adequate facilities are available, same-day CT or MRI colonography, or, in appropriate cases, doublecontrast barium enema would be desirable. However, same-day radiologic examination following colonoscopy frequently yields suboptimal quality when air insufflation is used for colonoscopy, due to retained air in the colon. If CO2 insufflation has been used, same-day radiologic imaging is generally feasible with appropriate quality. This avoids the necessity of scheduling the additional radiologic examinations on another day and further colon cleansing (Phaosawasdi et al. 1986; Rodney, Randolph & Peterson 1988)

In light of the above evidence and considerations: 

 Carbon dioxide insufflation is recommended for colonic endoscopic procedures (I - A).Rec 5.31

 Carbon dioxide insufflation should be avoided in patients with COPD, known C02 retention or otherwise reduced pulmonary function (VI - A).

Sedation and comfort

Flexible sigmoidoscopy 

Although flexible sigmoidoscopy is not currently recommended by the EU for colorectal cancer screening, previous results of ongoing trials indicate that screening is feasible and the procedure is well accepted by screenees ( UK Flexible Sigmoidoscopy Screening Trial Investigators 2002; Segnan et al. 2005; Weissfeld et al. 2005; Segnan et al. 2007; Hoff et al. 2009). No sedation for FS was used in these studies

Colonoscopy  

Colonoscopy can be an uncomfortable and distressing experience. These adverse effects can be reduced by careful patient preparation and sedation. 

Sedation improves patient tolerance of colonoscopy, particularly sedation using propofol combined with other sedative agents such as midazolam and analgesics such as pethidine and fentanyl (McQuaid & Laine 2008) (I). However, excessive sedation is considered to be an important contributor to cardio-respiratory related deaths following endoscopy in high-risk patients, particularly the elderly

According to Rex (Rex 2000b), most of the risk of colonoscopy is related to sedation. Cardiorespiratory complications are infrequent for patients without known heart or lung disease, but monitoring of oxygenation and blood pressure should be performed for all sedated patients.

Although hypoventilation, cardio-pulmonary events and vasovagal reactions may be related to pain and distension caused by the endoscopic procedure, in most cases they are more closely associated with the use of sedatives and opioids. Reduction in risk for these reactions has been observed in a study aimed to determine the incidence of such events when sedation is given only as required. All procedures in this study were performed by senior gastroenterologists with optimal equipment and nursing staff. Patients undergoing colonoscopy without sedation had less decline in blood pressure and fewer hypoxic episodes than sedated patients (Eckardt et al. 1999) 

Heavily sedated patients are more difficult to turn, and this may compromise caecal intubation and mucosal visualisation.

The available evidence indicates that the quality and safety of colonoscopy in patients that receive propofol sedation is comparable to that in patients receiving light, conscious sedation (or no sedation), provided patients given sedation are assessed properly prior to their procedure (McQuaid & Laine 2008; Singh et al. 2008) 

Propofol seems to be better than benzodiazepines or narcotics on recovery, discharge time and patient satisfaction and equivalent on procedure time, caecal intubation rate and adverse events (I). However, in many countries an anaesthesiologist is required for propofol administration.

It is recommended that there be local policies and processes in place to optimise sedation and patient support in order to maximise tolerance and minimise risk of complications

Image enhancing technology

There is conflicting evidence regarding the potential for narrow band imaging (NBI), Fuji Intelligent Chromo Endoscopy (FICE), and other techniques of image processing commonly referred to as “virtual chromoendoscopy” to improve detection and characterisation of high-risk lesions. One trial showed an increase in the detection rate of diminutive adenomas (Inoue et al. 2008). There was no difference in adenoma detection rates using NBI technique compared to white-light colonoscopy reported by other published trials (Johanson 2006; Rex 2006; Kaltenbach et al. 2008; Kaltenbach, Friedland & Soetikno 2008; Adler et al. 2009)

The use of autofluorescence was associated with a higher polyp detection rate compared with conventional endoscopy in one study, although the observed improvement was mainly attributable to an increased diagnostic yield of diminutive adenomas (Matsuda et al. 2008; Mayinger et al. 2008; McCallum et al. 2008)

Studies comparing the performance of colonoscopy with high definition versus standard colonoscopes did not show an increase in the detection rate of adenomas or hyperplastic polyps when using highdefinition instruments (East et al. 2008; Pellise et al. 2008; Burke et al. 2009)

The results of diagnostic accuracy studies showed better accuracy of NBI colonoscopy compared to standard colonoscopy in differentiating between neoplastic and non-neoplastic lesions (Su et al. 2006; Katagiri et al. 2008) (III). In the recent Cochrane review of chromoendoscopy, it was suggested that NBI may become the gold standard in enhanced techniques for detection of colorectal lesions, but with the advantage of reduced procedure time compared to chromoendoscopy. One trial comparing diagnostic accuracy of NBI with chromoendoscopy on 99 Patients has been retrieved (Tischendorf et al. 2007). The study did not find a significant difference in accuracy between the two technologies for the differentiation of neoplastic vs. nonneoplastic lesions. Further trials comparing NBI and chromoendoscopy are needed. 

Further experience and evidence about efficacy, benefits and potential adverse effects, as well as cost-effectiveness, are required before additional technologies can be recommended for routine, panEuropean use in colorectal cancer screening and diagnosis. Particularly in the screening context, improvements in detection and diagnosis may be accompanied by unacceptable decreases in specificity, and/or disproportionate, unacceptable increases in cost, measured both in human and financial resources. 

After sufficient standardisation of procedures and protocols in feasibility studies, pilot studies conducted in the framework of population-based screening programmes, and based on a randomised public health policy, could provide appropriate evidence to justify future recommendations for widespread implementation of new technologies. 

Chromoendoscopy

Widespread application of dye to the lumen of the colon (pan-chromoendoscopy) improves the detection of diminutive lesions (Brown, Baraza & Hurlstone 2007) (I). However, pan-chromoendoscopy is time consuming and the extra lesions detected may be unimportant clinically as a significant number of diminutive lesions may regress (Rother, Knopfle & Bohndorf 2007). The authors of a recent Cochrane review concluded that selective application of dye to suspicious areas (selective chromoendoscopy) may be more appropriate during colonoscopy

This approach is consistent with the conclusions of a recent international workshop which reviewed the role of non-polypoid lesions in the aetiology of colorectal cancer. The endoscopist should be skilled in recognising subtle changes in the appearance of the mucosal surface, particularly alterations in colour, vascularisation and morphology, to identify suspicious areas requiring dye spraying and to better detect polypoid lesions. Small patches of mucus may require rinsing to expose underlying suspicious areas worthy of staining, particularly in the right colon 

Selective chromoendoscopy with dye spraying on the lesion has been shown to be superior to conventional colonoscopy predicting polyp histology (Pohl et al. 2008) (III). Magnification chromoendoscopy is more effective than conventional chromocolonoscopy for diagnosing neoplastic colorectal polyps (Emura et al. 2007)

Cleansing and disinfection

Patients need to be reassured that decontamination processes are up to date and effective. Guidelines on cleaning and disinfection of endoscopes and endoscopic devices have been developed by the ESGE-ESGENA

It is recommended that decontamination policies and procedures be compliant with national or panEuropean guidelines based on accepted, published recommendations and standards and should be audited against defined indicators. The policies should be available in the endoscopy department and updated regularly

Kit - technologies for improving insertion of the colonoscope  

A variety of endoscope technologies may facilitate caecal intubation and improve patient tolerance. These include variable stiffness instruments, magnetic tracking devices and wire-guided techniques.

A recent meta-analysis (Othman et al. 2009) of variable stiffness colonoscopes identified seven randomised trials involving 1923 patients: four trials comparing adult variable stiffness colonoscopes with standard adult colonoscopes in adults, and three evaluating the paediatric variable stiffness colonoscope. The caecal intubation rate was higher with the use of variable stiffness colonoscopes. The variable stiffness colonoscope was associated with lower abdominal pain scores and decreased need for sedation during colonoscopy. Intubation times were unaffected by the variable stiffness colonoscope (I). The use of variable stiffness colonoscopes is recommended for screening colonoscopy

The present bibliographic search did not yield any relevant publications on improvement of completeness of colonoscopy through wire-guided techniques. This new technology has been investigated in endoscopic management of obstructive tumours 

Two RCTs of the magnetic endoscopic imaging (MEI) device showed improved performance of endoscopists, both with variable stiffness colonoscopy and with traditional colonoscopy, in terms of patient tolerance and caecal intubation rates, in particular when little or no sedation is used (Shah et al. 2000; Shah et al. 2002) (II). The utilisation of magnetic endoscope imaging (MEI) technology may be considered for patients requiring colonoscopy, particularly when little or no sedation is used 

Scheduling and choice

Booking processes must be robust to minimise late cancellations and failures to attend. To increase the chance of attendance an invitation for a primary screening test should be sent 2–3 weeks before the procedure is due, with an option for the patient to change the appointment if it is not convenient

Auditable outcome: Patient feedback on booking processes.  

Timelines 

A timely procedure is not critical in the context of primary screening but it is very important when endoscopy is performed following a previous positive screening test. A delayed procedure may not be critical biologically, but it can cause unnecessary anxiety for the screenee.

To ensure that patient anxiety is not unnecessarily increased, it is recommended that follow-up colonoscopy after positive screening be performed as soon as reasonably possible, but no later than within 31 days of referral (acceptable >90%, desirable >95%) 

Auditable outcome: Time taken from positive screening test to secondary endoscopic examination. If further pathological information is required before the decision to perform a colonoscopy, then the maximum and the desirable targets of four and two weeks, respectively, should be timed from the receipt of the pathology report. The pathology report should be delivered to the screening programme within two weeks.  

Environment 

The environment should be conducive to a good experience and efficient processing. It should be physically comfortable, offer privacy and there should be facility to hold private conversations with screenees and their relatives. The reception and assessment areas should be separate from recovery facilities 

Auditable outcomes: patient feedback on environment and patient turn around times. 

During the procedure 

There is an increasing body of evidence demonstrating unacceptable miss rates of cancer following colonoscopy. Miss rates vary between endoscopists suggesting that care with the examination and technique play a key role in ensuring cancer is not missed.

Endoscopists must have a mix of technical, knowledge and judgement competencies to identify and successfully remove high-risk lesions. Ideally they will perform a complete examination quickly, safely and with minimal discomfort, leaving time to properly inspect the colon, and safely remove and retrieve lesions. They will identify all abnormal areas, characterise them and make a judgement of what to do. They will then, if it is appropriate to do so, safely remove and retrieve all neoplastic lesions 

Providing such high-quality and safe endoscopy requires a team approach with appropriate equipment immediately to hand. The nursing support team must ensure the patient is comfortable and has stable observations to allow the endoscopist to devote his attention to the procedure. The nurses also provide important technical support ensuring endoscopy equipment is serviceable and that all the necessary accessories are readily available. Finally they play an important role supporting the endoscopist during therapeutic procedures. Both endoscopist and nurse should regularly reflect on their practice together with pathology and surgical teams in order to optimise patient outcomes. 

Colonic cleansing

Inspection of the colon requires careful preparation removing colonic contents to optimise the safety and quality of the procedure. Ideally there should be no residual stool or liquid in the lumen that could mask any suspicious area.  

Flexible sigmoidoscopy 

The ongoing European sigmoidoscopy trials adopted a bowel preparation based on a single enema, self-administered at home within two hours from the appointment, or, in one case, at the screening centre.

No studies were found assessing the effect of having the enema performed directly at the screening centre, although this represents an option that might enhance participation by reducing patient’s concerns and enhancing engagement. Available evidence from one controlled trial did not indicate that using two enemas (the first the night before the test and the second two hours before the scheduled time for the exam) affects participation compared to using a single enema (Senore et al. 1996). Oral preparation was associated with a reduced participation in a large screening trial, compared to enema (Atkin et al. 2000). Adding oral preparation to the enema resulted in reduced participation (Bini et al. 2000). 

No difference in the proportion of inadequate exams was observed when comparing a single enema regimen to a preparation using two enemas or to oral preparation. 

Bowel preparation for screening sigmoidoscopy should involve a single procedure, either enema or oral preparation (II). A single self-administered enema seems to be the preferred option, but cultural factors should be taken into account, and patient preferences should be assessed 

Colonoscopy  

Data on the impact of different preparation regimens in the context of population screening with colonoscopy are lacking. A recent systematic review concluded that no single bowel preparation emerged as consistently superior. Sodium phosphate was better tolerated (Belsey, Epstein & Heresbach 2007), but safety alerts on its use have recently been issued by the US FDA and Health Canada. The authors identified a general need for rigorous study design to enable unequivocal conclusions to be drawn on the safety and efficacy of bowel preparations.

Timing of administration of the recommended dose appears important, as it has been established that split dosing (the administration of at least a portion of the laxative on the morning of the examination) is superior to dosing all the preparation the day before the test, both for sodium-phosphate and polyethylene glycol (Aoun et al. 2005; Parra-Blanco et al. 2006; Rostom et al. 2006; Cohen 2010)

A systematic review (Belsey, Epstein & Heresbach 2007) of different bowel cleansing regimens identified no significant differences other than improved patient tolerance of sodium picosulphate preparations. Furthermore, there are no preferred methods of assessing the effectiveness of bowel cleansing. Care must be taken however with some agents (i.e. phospho prep) in certain patient groups, especially the elderly and those with renal failure, due to potential renal side effects (WHO 2009)

Patient information and consent

Information in this context includes information related to the endoscopic procedure and should include why the procedure is being done, what it involves, preparation for the procedure, and the risks. The patient should be told what he/she might expect to happen after the procedure (including contact details in case of emergency) and the plan of aftercare. The patient should be informed about the options for sedation and how this might affect their perception of the procedure and the associated restrictions on travelling home.

The consent process involves an explanation of the procedure, the potential benefits, the risks and possible consequences. Consent for endoscopic procedures begins with a recommendation to have the examination, and ends when the procedure is complete. The individual must have the opportunity to withdraw consent at any stage during this process. 

The key elements of patient information for endoscopy include: 

•  considerations related to current medications including anticoagulants and antiplatelet agents;
• considerations related to previous medical illnesses;
•  the benefits of the test; how to prepare for the procedure (including bowel cleansing); 
•  the nature of the procedure and what it involves;
•  possible adverse events including discomfort and complications; 
•  what support the patient may need after the procedure, particularly if they are sedated; 
• and the importance of not driving or making important decisions after sedation. 

Support services

Only rarely will a person undergoing a primary screening procedure require admission to hospital for further care. Thus it is not necessary to have medical support facilities close at hand. However, services performing endoscopy in more remote settings must have robust guidelines and processes in place to enable patients to be resuscitated effectively and be transferred rapidly and safely to a hospital where surgical services are available. On this basis it is recommended that any screening service, regardless of setting, should make an assessment of risks and develop the ability to respond to emergencies

While there are no absolutes, a case can be made for delivering high-volume screening endoscopy outside traditional hospital settings to improve the patient experience and to reduce healthcare and societal costs. In contrast, risk assessments will indicate that colonoscopy following a positive FOBT or a positive FS is a more complex procedure that is associated with higher risks and should, therefore, be performed in acute hospital settings. 

Audit and quality improvement  

This section proposes that endoscopy services monitor key outcomes to ensure that a high-quality and safe service is being provided and to identify areas in need of improvement. Two terms are used for such outcomes: auditable outcomes and quality indicators. An auditable outcome refers to an outcome that should be measured, but for which there is not an evidence base to recommend a standard, such as the comfort of the procedure. A quality indicator is an outcome for which there is a sufficient evidence base to recommend a standard, such as caecal intubation rate.

It is expected that some auditable outcomes will become quality indicators as the evidence base improves, and that the standards of quality indicators will rise as standards improve. 

On the basis of this, it is recommended that all screening programmes should have processes in place for monitoring, auditing, reviewing and acting upon key auditable outcomes and quality indicators in the following areas 

• Quality; 
•  Safety; and 
•  Patient feedback  

Patient considerations

Patients generally prefer services that are close to home and easily accessible. Thus high-volume screening endoscopy is probably best situated closer to the population to be screened. In contrast, level 3 and 4 expertise for removing high-risk lesions is likely to be provided at district and regional levels respectively. The priority here is the facility and expertise, not proximity. 

When implementing high-volume screening endoscopy consideration should be given to locating services in convenient locations for patients to maximise engagement in screening

Possible destabilising effect on symptomatic services

Unplanned introduction of screening endoscopy (at whatever level) creates additional demand and may lead to destabilisation of the symptomatic service. Thus, if endoscopy for screening is introduced alongside symptomatic services, care must be taken to ensue there is sufficient new capacity. 

An assessment of the impact of demand from screening on waiting times for symptomatic patients should be made to ensure that there is sufficient planned new capacity such that screening does not lengthen waits for symptomatic patients

Infrastructure and efficiency 

The infrastructure requirements for high-volume screening endoscopy need to cater to large numbers of presumptively healthy people. High-volume screening endoscopy requires efficient booking, assessment and recovery processes to function effectively without compromising the patient experience. Thus, it may be advantageous for high-volume screening activities to be separated from routine clinical endoscopy and follow-up endoscopy of screen-positives. 

The need for sedation

The level of competency to perform high-quality endoscopy and to remove high-risk lesions is also dependent on the competency of the support team and the available equipment: a highly competent endoscopist requires equally competent support staff and the right equipment and supplies to perform the procedure and deal with any problems that might arise (such as clips for uncontrolled bleeding).

 It is recognised that the methodology does not currently exist to reliably recognise who has achieved the proposed levels of competence. Thus, until a competency–based assessment process is available the clinical lead of the service should be satisfied that: 

 the professionals have the necessary competence;

 the unit has the necessary equipment; and

 in the event of a serious adverse event, it will be possible to manage the patient locally or transfer the patient safely to another institution with the expertise and facilities to care for the patient. 

A review of capabilities may identify shortcomings that can be addressed with further training or investment . This training and investment should occur before screening begins.

The need for sedation

The use of sedation for lower gastrointestinal endoscopic procedures varies between European countries. Three main patterns are readily discernible:

 infrequent use of sedation;

 frequent use of conscious sedation with opiates and benzodiazepines; 

and almost exclusive use of deep sedation with propofol or general anaesthesia.

QUALITY ASSURANCE IN ENDOSCOPY

The colonoscopist needs to judge whether he/she is competent to remove a lesion and whether it is safe to remove the lesion in this setting. On the basis of good practice it is recommended that if there is doubt, the lesion must be appropriately documented and the patient referred elsewhere to have the lesion removed

Thus, when considering where endoscopic screening services are to be located, the commissioner should be aware of how often a patient may need to be referred elsewhere. If it is expected that referral somewhere else will be a frequent occurrence (perhaps >1% of patients) then it is better to consider locating the service elsewhere, i.e. where the competence of the available endoscopists would permit less referral. 

To help in the planning of location of endoscopic services for screening, the following five levels of competency are proposed. 

Level 0: The operator does not remove any lesions, referring on all patients with any detected lesions. The operator will be able to biopsy lesions, and pathological material may inform the decision to refer. Basic level of competency for diagnostic FS but not recommended for screening FS. 

 Level 1: Removing lesions <10 mm in diameter at FS. Rationale: larger lesions will indicate a need for colonoscopy and can be removed when the colonoscopy is performed. Tissue is required from smaller lesions to decide whether colonoscopy is necessary. Thus any person performing FS screening should have this level of competency. 

 Level 2: Removing polypoid and sessile lesions <25 mm providing there is good access. All colonoscopists should have this level of competency. 

 Level 3: Removing smaller flat lesions (<20 mm) that are suitable for endoscopic therapy, larger sessile and polypoid lesions, and smaller lesions with more difficult access. Some flat lesions <20 mm with poor access might be unsuitable for this level. Any person doing colonoscopy for positive FOBT in a screening programme should have this level of competency. 

 Level 4: Removing large flat lesions or other challenging polypoid lesions that might also be treated with surgery. This is the type of lesion that would not be removed at the first colonoscopy because of time constraints, if applicable, or because the surgical option needs to be discussed with the patient. If the patient chooses to have endoscopic therapy, then he/she should be referred to a level 4 competent endoscopist. This level of competency would be expected of only a small number of regionally based colonoscopists. 

In the context of colorectal screening and diagnosis in Europe, units only providing Level 0 competencies are not recommended, because unnecessary endoscopic procedures would be required to remove small lesions which could have been removed during the initial FS. Furthermore, unnecessary colonoscopies may be encouraged in the absence of histopathological evaluation of small lesions left in place during the initial FS. 

Effect of screening modality on the provision of endoscopic services for screening

Colonoscopy is the recommended test for follow-up investigation for individuals who have tested positive with other CRC screening tools (FOBT, Flexible sigmoidoscopy (FS), and also in experimental studies assessing potential screening tools, e.g. DNA faecal markers and CT colonography). Highquality endoscopy (colonoscopy and flexible sigmoidoscopy (FS)) is also used in some Member States as a screening tool for colorectal cancer. The frequency of endoscopy when used as a primary screening tool will be much higher than endoscopy used as a follow-up investigation of another screening test. Thus the phrase ‘high-volume screening endoscopy’ will be used to refer to endoscopy used as a primary screening tool and ‘low-volume screening endoscopy’ will be used to refer to follow-up endoscopy. However, it is recognised that if the test positivity rate in a FOBT screening programme is high a large volume of colonoscopies will be generated. The key practical difference of these high- and low-volume populations requiring endoscopy in a screening context is the probability of identifying and nature of high-risk lesions

The setting in which the endoscopic procedure will be performed will be determined by: 

 quality and safety determinants;

 the need for sedation; 

 patient-oriented factors; 

 possible impact on symptomatic services; 

 infrastructure and efficiency; 

 staff competencies and equipment; and

 availability of support services. 

Quality and safety 

Diagnostic procedures, both flexible sigmoidoscopy and colonoscopy, can be performed safely in diverse clinical settings. When providing services for a colorectal cancer screening programme, the key consideration is what facilities and level of competence are required to remove high-risk lesions. Removing large high-risk lesions safely requires a considerable level of competence and appropriate support close at hand when a complication occurs. For example, it would be inappropriate to remove large or difficult high-risk lesions if the colonoscopist is only rarely faced with such a lesion (as in highvolume, low-risk population screening) or if the procedure is being done in a remote setting. 

Screening algorithm

 Sample and test numbers 

Few studies have examined the number of stool specimens necessary to optimise the diagnostic performance of FOBT. Consideration should be given to using more than one specimen together with criteria for assigning positivity which together provide a referral rate that is clinically, logistically and financially appropriate to the screening programme. The clinical sensitivity and specificity of testing can be modified depending on how the test data are used. Guaiac-based tests typically use 3 stools, but an algorithm using additional tests can be used to adjust clinical sensitivity and specificity

Determining test positivity 
The choice of a cut-off concentration to be used in an immunochemical test to discriminate between a positive and negative result will depend on the test device chosen, the number of samples used and the algorithm adopted to integrate the individual test results. Whilst an increasing number of studies are reporting the experience of different algorithms, local conditions, including the effect on sample stability of transport conditions, preclude a simple prescribed algorithm at this time. Adoption of a test device and the selection of a cut-off concentration should follow a local pilot study to ensure that the chosen test, test algorithm and transport arrangements work together to provide a positivity rate that is clinically, logistically and financially acceptable

QUALITY ASSURANCE IN ENDOSCOPY

Guiding principles for a colorectal screening endoscopy service 

1. People undergoing endoscopy, whether for primary screening, for assessment of abnormalities detected in screening, for assessment of symptoms, or for surveillance, should have as good an experience as possible, permitting them to encourage screening, assessment and surveillance of appropriate quality to their friends, family and colleagues. 

2. The provision of the service must take into account the perspectives of endoscopists and public health to ensure that the experience is high-quality, safe, efficient as well as person-oriented. 

3. Provision of screening should take account of historic development within different local and cultural contexts.