High Definition Endoscopy With i-Scan for Small Colonic Polyp Evaluation: The HiScope Study (HiSCOPE)

February 25, 2013 updated by: Pradeep Bhandari, Portsmouth Hospitals NHS Trust

A Prospective Single-blind Observational Cohort Study of High Definition White Light Endoscopy and i-Scan Image Enhancement for the Characterisation of Small Colonic Polyps

Current standard practice is to remove all colonic polyps found during colonoscopy as it has not been possible to distinguish between polyps with some malignant potential (adenomatous) and those with negligable malignant potential (non-adenomatous).

Recent advances in endoscope imaging and technology have allowed endoscopists to distinguish between these two types of polyps by examining minute surface details.

i-Scan is a new digital enhancement method that aims to enhance surface details and may enable similar accurate distinction between adenomatous and non-adenomatous polyps.

Hypothesis:

High definition white light endoscopy plus i-Scan improves diagnostic accuracy of in-vivo assessment of colonic polyps <10mm in size over high definition white light endoscopy alone.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Traditionally all polyps detected at colonoscopy, except obvious cancers, have been removed. It is felt that small (<10mm diameter) hyperplastic polyps cannot be reliably distinguished from adenomatous polyps by endoscopists [1]. Therefore a large number of hyperplastic polyps are removed unnecessarily. This results in increased risk to patients through exposing them to unnecessary polypectomy, and increased cost to the health service through the cost of processing greater numbers of histopathology specimens. The cost per specimen is around £58.

This challenge of distinguishing small hyperplastic polyps from small adenomatous polyps has been met over the past decade through the use of novel chromoendoscopy and computed 'virtual chromoendoscopy' techniques.

Chromoendoscopy involves using staining or contrast dyes to highlight the minute surface patterns in the mucosa of the gastrointestinal tract. The dyes are applied to the colonic mucosa via the working channels of the endoscope. Vital stains such as cresyl violet and methylene blue, which are taken up into epithelial cells, have been used by Japanese endoscopists for many years. Work by Kudo et al showed that by using these stains in combination with magnification endoscopy the minute 'pit patterns' of colonic mucosal lesions could be precisely examined and classified. The pits described are the surface opening of the mucosal crypts. Kudo showed that the surface pit pattern could predict the histology of a lesion with high accuracy [2-4], enabling distinction between adenomatous and hyperplastic polyps. Concerns regarding potential harmful effects of vital stains increased the popularity of an alternative chromoendoscopy dye, indigocarmine [5]. Indigocarmine is not taken up by cells but lies on the colonic wall. Studies from East Asia, the USA and Europe published in the early part of the last decade showed that by combining indigocarmine and magnification endoscopy, neoplastic colonic polyps (adenomas) could be distinguished from non-neoplastic hyperplastic polyps with accuracy rates of 68-96% [6-10]. By the same method, surface patterns could also identify small early colorectal cancers[11] . Subsequent studies demonstrated that indigocarmine could adequately distinguish between adenomatous and hyperplastic polyps without the need for optical magnification [12-15].

During the past few years new methods of closely examining lesions within the colon have been developed. Digital imaging techniques or 'virtual chromoendoscopy' systems have been developed by endoscope manufacturers as a 'push-button' alternative to chromoendoscopy dyes, being potentially simpler and quicker to use. The first of these novel technologies available was the narrow band imaging (NBI) system produced by Olympus. A filter within the endoscope selects out narrow bandwidths of blue and green light, and thus reduces red light. These wavelengths penetrate only the superficial layers of the mucosa, highlighting surface patterns and microvasculature. Adenomatous polyps have more numerous and prominent microvessels in comparison to hyperplastic poylps. This system has been shown to be effective in differentiating small hyperplastic and adenomatous polyps with accuracies of 91 - 94% [16-23].

The Fujinon Intelligent Colour Enhancement (FICE) system developed by Fujinon uses post-processor electronic colour filter technology to allow a range of filter images with different wavelengths of light to be viewed. Similar results to NBI have been achieved in the characterisation of small polyps [13, 24, 25].

More recently a further virtual chromoendoscopy system, i-Scan has been developed by Pentax. i-Scan identifies areas of contrast between adjacent pixels (ie light bordering dark) and enhances this contrast. Additionally in a similar method to FICE, post-processor manipulation of the red, green and blue components of the spectrum is used to enhance vessels and surface structures.

A single study from Germany has suggested that i-Scan improves the detection of lesions during flexible sigmoidoscopy and can accurately predict histology. There is a need for further data on the clinical efficacy of i-Scan in the assessment of colonic polyps, particularly in a UK population and in a bowel cancer screening population, neither of which have been studied to date.

Through the use of these new technologies it may be possible to accurately predict the histology of small polyps in real time. Once an in-vivo diagnosis has been made with high confidence it may be possible for small hyperplastic polyps to be discarded, rather than sent for histological analysis, or to be left in situ [22]. This has potential benefits in reducing the frequency and consequent risk of polypectomy for patients and could also reduce pathology costs. UK and US guidelines for repeat surveillance colonoscopy after adenomas are detected at baseline examination are based on the number and size and histology of adenomas [26, 27]. At present these 'rescope intervals' are determined once the histology report of any resected polyps is received. With accurate in-vivo diagnosis these intervals may be set immediately after the baseline colonoscopy has been completed.

Whilst the development of these endoscopic advanced imaging technologies is to be welcomed, it is important for studies to determine what can be achieved through their use, over and above standard white-light colonoscopy. The American Society for Gastrointestinal Endoscopy has identified the utility of technologies used in the real-time assessment of diminutive (<5mm) colonic polyps as a key area for study, and has published guidelines on the minimum standards which new endoscopic technologies should meet before their use becomes widely adopted [28].

We aim to evaluate HDWL and HDWL + i-Scan for the real time assessment and prediction of histology of small colonic polyps in a BCSP population.

Study Type

Observational

Enrollment (Actual)

84

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

60 years to 74 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

UK Bowel Cancer Screening patients attending for colonoscopy

Description

Inclusion Criteria:

  • Patients found to have colonic polyps up to 10mm in size

Exclusion Criteria:

  • Poor bowel preparation
  • Inflammatory bowel disease
  • Polyposis syndrome

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Cohort
  • Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Diagnostic Accuracy of In-vivo Polyp Assessment
Time Frame: Once histopathology results are known, approximately 2 weeks after in-vivo assessment
Diagnostic accuracy of in-vivo assessment of colonic polyps <10mm in size using high definition white light endoscopy and high definition white light endoscopy plus i-Scan image enhancement. Accuracy compared to the gold standard of histopathology. Accuracy - number of polyps with histology correctly predicted by in-vivo method/total number of polyps assessed (Expressed as a percentage)
Once histopathology results are known, approximately 2 weeks after in-vivo assessment

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Sensitivity for Adenomatous Histology of Colonic Polyps <10mm in Size
Time Frame: Once histopathology results are known, approximately 2 weeks after in-vivo assessment
Sensitivity for adenomatous histology of in-vivo assessment of colonic polyps <10mm in size using high definition white light endoscopy and high definition white light endoscopy plus i-Scan image enhancement. Sensitivity compared to the gold standard of histopathology. Senstivity for adenomatous histology = number of correctly identified adenomas (true positives)/total number of adenomas (true positives + false negatives)
Once histopathology results are known, approximately 2 weeks after in-vivo assessment
Specificity for Adenomatous Histology of Colonic Polyps <10mm in Size
Time Frame: Once histopathology results are known, approximately 2 weeks after in-vivo assessment
Specificity for adenomatous histology of in-vivo assessment of colonic polyps <10mm in size using high definition white light endoscopy and high definition white light endoscopy plus i-Scan image enhancement. Specificity compared to the gold standard of histopathology. Specificity for adenomatous histology = number of correctly identified non-neoplastic polyps (true negatives)/total number of non-neoplastic polyps (true negatives + false positives)
Once histopathology results are known, approximately 2 weeks after in-vivo assessment
Negative Predictive Value for Adenomatous Histology of Rectosigmoid Polyps ≤5mm in Size
Time Frame: Once histopathology results are known, approximately 2 weeks after in-vivo assessment
Negative predictive value for adenomatous histology of rectosigmoid polyps ≤5mm in size using high definition white light endoscopy and high definition white light endoscopy plus i-Scan image enhancement. NPV compared to the gold standard of histopathology. Negative predictive value = number of true negatives/(number of true negatives + number of false negatives)
Once histopathology results are known, approximately 2 weeks after in-vivo assessment

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Accuracy of Prediction of Polyp Surveillence Intervals
Time Frame: Once histopathology results are known, approximately 2 weeks after in-vivo assessment
Accuracy of prediction of post-polypectomy surveillence colonoscopy intervasl based on national guidelines. Intervals based on in-vivo assessment of all polyps ≤5mm in size combined with histopathology of polyps >5mm in size will be compared to intervals determined by histopathology of all polyps
Once histopathology results are known, approximately 2 weeks after in-vivo assessment

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Portsmouth Hospitals NHS Trust

Investigators

  • Principal Investigator: Pradeep Bhandari, MBBS, Portsmouth Hospitals NHS Trust

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

May 1, 2011

Primary Completion (Actual)

May 1, 2012

Study Completion (Actual)

May 1, 2012

Study Registration Dates

First Submitted

January 3, 2013

First Submitted That Met QC Criteria

January 3, 2013

First Posted (Estimate)

January 4, 2013

Study Record Updates

Last Update Posted (Estimate)

April 4, 2013

Last Update Submitted That Met QC Criteria

February 25, 2013

Last Verified

February 1, 2013

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • PHT/2009/046

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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