Endoscopy

Obtaining bowel preparation for endoscopy screening 

The bowel preparation may be obtained from the office of the primary health care provider (e.g. GP), from endoscopy units or other screening facilities, or from pharmacists. There is no evidence concerning the impact of any of these strategies on participation rate, or on the proportion of inadequate exams. The aim should be to maximise accessibility taking into account local conditions, setting and culture. Several providers close to the target population should be available

Bowel preparation for sigmoidoscopy 

The acceptability of different types of preparations is influenced by cultural factors, which should be considered together with the evidence concerning the effect of the preparation, when choosing among different options. 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

Summary of evidence 

 A bowel preparation regimen using a single enema self-administered at home two hours before the endoscopy has been reported as the most acceptable option (II). 

 Using two enemas may not decrease participation, while a preparation using both oral preparation and enema has a negative effect on compliance (II). 

Bowel preparation for colonoscopy 

Data on the impact of different preparation regimens in the context of population screening with colonoscopy are lacking. A recent systematic review (Belsey, Epstein & Heresbach 2007) concluded that no single bowel preparation emerged as consistently superior, but sodium phosphate was better tolerated.

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) (II)

Summary of evidence 

 To date no single bowel preparation for colonoscopy has emerged as consistently superior over another in terms of efficacy and safety (I) although sodium phosphate may be better tolerated and it has been shown that better results are obtained when the bowel preparation is administered in two steps (the evening before and on the morning of the procedure) (II).  

Test interpretation and reporting  

Inadequate test 

An operational definition for an inadequate screening test should be made explicit in the programme protocol, taking into account the characteristics of the test as well as the testing procedure adopted . 

Defining a negative test and episode result 

An explicit protocol defining the conditions for classifying a test as negative should be adopted, specifying the criteria for referral to colonoscopy assessment (in FS-based programmes) or surveillance (TC-based programmes).

Also, an operational definition for a negative screening episode should be made explicit in the programme protocol. A screening episode should be classified as negative when, based on the results of the primary test or of the recommended assessments (if any), the subject is referred again to the standard screening protocol. The rationale for having such pragmatic definition is to avoid the risk of labelling people detected with lesions that do not have clinical and prognostic significance