As discussed in Chapter 1, Current service provision, and Chapter 5, The decision problem, it is known that the majority of hospitals that perform endoscopy currently possess endoscopy systems capable of VCE. Implementation of the technology will therefore not require large-scale replacement of equipment. However, not all systems currently in use comprise fully HD components (i.e. endoscope, light source, video processor, visual display monitor, cabling). Optimum image quality will be attained by fully HD systems, and in some centres this may not be achieved until all equipment is routinely upgraded.
The PIVI statement requires that polyp images taken during VCE should be permanently stored and should be of sufficient resolution to support the endoscopists’ assessment and clinical decisions.32 Therefore, hospitals would need to implement systems to permit adequate electronic storage of HD images linked to patients’ files to allow future re-examination if necessary.
In terms of patient issues and preferences, some patients find colonoscopy to be an uncomfortable experience and, therefore, may prefer that VCE is not used if it may potentially increase the time taken to do the procedure (e.g. the time needed for the endoscopist to inspect the image on the monitor before making a characterisation rather than just resecting it). However, there were very few data from the studies included in our systematic review on differences between procedure times between modes of polyp assessment to provide conclusive evidence.
It is possible that some patients may experience anxiety knowing that a polyp, even one characterised as hyperplastic, has not been resected. Some patients may prefer that all polyps are removed, even when there is negligible risk of them becoming cancerous (notwithstanding the fact that some endoscopists currently leave hyperplastic diminutive polyps in situ, as noted earlier, in Chapter 1 of this report). This would not prohibit VCE from being used as part of optical assessment, but would mean that a full DISCARD strategy (i.e. leaving in situ hyperplastic polyps in the rectosigmoid colon) would not be possible for such patients. If a DISCARD strategy is to be implemented there may be a requirement for patient information about the procedure, and the opportunity for discussion between patient and endoscopist before the colonoscopy.
Although VCE is currently used in some centres to characterise colorectal polyps, its more widespread use would require greater availability of training and auditing to ensure appropriate use. As discussed in Chapter 1, Training in the use of virtual chromoendoscopy, current training practices vary in terms of mode and duration, and studies have illustrated the presence of a learning curve to attain acceptable levels of diagnostic accuracy. The manufacturer of NBI suggests that training of up to 2 days in duration would be sufficient for initial training. However, expert clinical advice suggests that for some endoscopists allocating that amount of time for training might not be realistic because of busy work schedules.
Not all endoscopists may want to assume the responsibility for characterising colorectal polyps and leaving those considered to be hyperplastic in situ. If VCE is to be recommended in the NHS there may be a need for awareness raising and incentives to encourage greater acceptance and use of this technology in practice.
