Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT01182623 |
| Other study ID # |
PHT2009/046 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
December 2009 |
| Est. completion date |
September 30, 2010 |
Study information
| Verified date |
April 2023 |
| Source |
Portsmouth Hospitals NHS Trust |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational
|
Clinical Trial Summary
It is current practice to remove any polyps found during colonoscopy. This is because
adenomatous polyps have the potential to turn into cancer. However, a proportion of polyps
<10mm in size are hyperplastic, which cannot turn into cancer. Current practice requires
these to be removed, as it is traditionally felt that they cannot be separated clinically
from adenomas. This increases the risk of perforation and results in a significant cost in
processing the samples. However, it has been suggested that it is possible to differentiate
neoplastic from non neoplastic lesions using skills in polyp surface pattern recognition. If
this is the case the investigators may be able to reduce the need for polypectomy The
investigators believe that it is possible to tell the difference between polyps with
cancerous potential and those that are harmless by assessment of surface patterns. This may
enable us to improve the investigators clinical decisions when assessing polyps during
colonoscopy, and reduce the number of unnecessary polypectomys being performed.
Description:
Polyps are a common finding during colonoscopy. It is current practice to remove these
lesions, as some have the potential to turn into cancer. However, not all polyps are the
same. Polyps can be of three different types:
1. Hyperplastic, which have negligible potential to turn into cancer and if left would
cause no harm. These account for around one third of all small polyps encountered
2. Adenomas, which can turn into cancer and should be removed
3. Polyp cancers, which should be either biopsied or removed completely
The management pathway for polyps >10mm is very simple as they are either likely to be
adenomas which need removal or cancers which need a biopsy and tattoo. There is a rare
possibility of these big polyps being hyperplastic / serrated adenomas and given the risk of
malignant transformation, they need removal as well.
It has been traditionally felt that hyperplastic polyps cannot be separated clinically from
adenomas or polyp cancers by the endoscopist. It is for this reason that all polyps are
removed. However, polypectomy increases the risk of perforation and results in a significant
cost in processing the samples. Recently it has been suggested that it is possible to
differentiate neoplastic from non neoplastic lesions in the colon using skills in polyp
surface pattern recognition.
Kudo's pit pattern is an effective way of in-vivo prediction of histology and differentiating
neoplastic from non neoplasic polyps. However, it was originally described using vial
staining which is cumbersome, time consuming and is not possible to perform outside Japan due
to lack of availability and fears of toxicity related to gentian violet. It does however
produce excellent results when used for pit pattern recognition. (Hurlstone DP C. S., 2004)
It works by irreversibly binding microbial DNA and directly inhibiting cell replication.
(Wakelin LPG, 1981).
Gentian violet is not the only way to examine the surface patterns of polyps. Many of the
features can be seen with white light endoscopy. (Fu KI, 2004). Furthermore, there is
extensive experience with other dies which are commonly used in Western Europe. Indigo
carmine dye spray has been performed in studies in Japan, and has proven to be very effective
in the assesment of polyp characteristics. It has been used for over 14 years in colonoscopy
(Axelrad, 1996). Overall diagnostic accuracy by conventional view, chromoendoscopy and
chromoendoscopy with magnification ranged from 68% to 83%, 82% to 92%, and 80% to 96%,
respectively. (Axelrad AM, 1996) (Tung SY, 2001) (Eisen GM, 2002) (Su MY, 2004) (Apel D,
2006). It has the advantage over gentian violet that it does not bind to tissues and is
therefore very safe. It has been questioned whether widespread applications of the techniques
could influence the indications for biopsy sampling during colonoscopy and the indication for
mucosectomy (Yasushi Sano, 2005).
When compared to standard colonoscopy, indigo carmine chromoendoscopy, with magnification,
has been shown to increase the accuracy for polyp differentiation from 84% to 96% (Fu KI,
2004). High-resolution indigo carmine chromoendoscopy demonstrated a small increase in
accuracy over chromoendoscopy without magnification from 81% to 83% . (Hurlstone DP K. M.,
2005).
Because of its numerous benefits in lesion detection and assessment of polyps indigo carmine
has become a standard part of colonoscopy and is recognised by the British Society of
Gastroenterology as an important skill for the practicing endoscopist. It has become standard
practice within Portsmouth Hospitals NHS trust when performing colonoscopy. This is a
position which is reflected nationally in most large units which participate in the bowel
cancer screening programme.
White light endoscopy and chromoendoscopy are not the only methods of examining colonic
polyps. Computed virtual colonoscopy, where a video computer processor within the endoscopy
equipment enhances the endoscopic picture have become commonly available. There are systems
available from all of the main endoscope manufacturers, including narrow band imaging from
Olympus and i-scan from Pentax. Fujinon has developed a very effective post processor
technology called FICE which helps define the surface pattern of polyps in great detail. This
is now a standard feature on all of the endoscopes produced by the company. It has been shown
in a limited number of studies to offer a potentially useful alternative to dye spray in
predicting in-vivo histology. (J. Pohl, 2008). A prospective randomised multicentre study
looked at 764 patients with FICE compared to white light with targeted indigocarmine spray.
It found that FICE and indigocarmine were both able to differentiate adenomas from neoplasia.
There was a sensitivity in differentiating adenomas from non-neoplastic polyps of 92.7%,with
FICE, comparable but not superior to that of indigocarmine (90.4%), with no statistically
significant difference between the two techniques observed. (p=0.44.) FICE did not shorten
the procedure time. A prospective series looking at FICE in the evaluation of colononic
polyps up to 2cm in size by the same team suggested a sensitivity of 89% could be achieved.
Unfortunately these studies looked at larger lesions and therefore it is difficult to say
whether this could be achieved with polyps <1cm, where accurate assessment is clearly more
difficult. However, it is in the smaller lesions where the greatest gain in terms of a change
in management exists. (Pohl J N.-T. M., 2008).
It is generally accepted that further research is needed in this field. If it is possible for
endoscopists to differentiate neoplastic from non neoplastic polyps the potential benefits
both in terms of safety and histopathology costs would be significant. The current policy of
polypectomy or biopsy of all polyps detected during colonoscopy is a very expensive option (£
80-120) and carries a significant risk of perforation.
Within Portsmouth Hospitals NHS trust it has become standard practice to assess all polyps
with FICE and dye spray with indigo carmine prior to removal. This is consistent with current
guidelines from the British society of Gastroenterologists and is important both in the
detection and assessment of polyps. These techniques are established and their importance in
colonoscopy is not under investigation. What is unclear is whether endoscopists are able to
differentiate neoplastic from non-neoplastic lesions on a basis of surface pattern
recognition accurately enough to be able to change clinical practice.
We aim to assess the impact of surface pattern assessment on the potential management of
patients, and whether it has the potential to safely replace the policy of biopsy /
polypectomy for pateints with polyps <10mm in size.
