Study of Narrow Band Imaging in the Characterization of Residual Neoplasia After Endoscopic Piecemeal Mucosal Resection

Study Overview
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Brief Summary
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This study is designed to evaluate the diagnostic accuracy of Narrow Band Imaging (NBI) compared with High Definition White Light colonoscopy (WLE) for detection of residual neoplasia in subjects with piecemeal polypectomy scars.

Detailed Description
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Resection of large sessile polyps in the colon (usually more than 2 cm) or those nonpolypoid neoplastic lesions (also called laterally spreading tumors or LST), confers technical difficulty and often are forced to remove into fragmented resection or endoscopic piecemeal mucosal resection. This has been associated with a recurrence of 25%. For this reason, clinical guidelines recommend endoscopic follow-up at 2 to 6 months after piecemeal resection of colorectal polyps to check for residual neoplasia. Narrow-Band Imaging (NBI, Olympus) improves visibility and identification of the surface and vascular structures of colon polyps. In contrast to conventional chromoendoscopy, it is easily activated by pressing a button on the endoscope. Virtual or conventional chromoendoscopy are applied during resection of polyps defining the border of the lesion. However, there are few studies using Narrow Band Imaging and do not allow to know whether the use of this technique could improve the detection of residual tumor after fragmented polypectomy and avoid complications, time and costs of biopsy and histological analysis. In this context, the European Society of Gastrointestinal Endoscopy (ESGE) has recently published the first Guideline of Advanced Endoscopic Imaging for the Detection and Differentiation of Colorectal Neoplasia and recommends conventional or virtual chromoendoscopy in patients with piecemeal polypectomy scar (strong recommendation, low quality evidence). The investigators will perform a randomised, controlled trial of tandem colonoscopy using NBI and WLE. The main goal is to compare the rate of detected neoplasia between both techniques and evaluate the diagnostic accuracy of NBI and WLE to histology as the gold standard.

Official Title
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Randomised Tandem Colonoscopy of Narrow Band Imaging (NBI) and White Light Endoscopy in Patients With Endoscopic Piecemeal Mucosal Resection

Conditions
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Colorectal Neoplasms

Intervention / Treatment
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* Device: WLE
* Device: NBI


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients over 18 years old who underwent a colonoscopy for any reason in the last 12 month Patients with a basal colonoscopy findings: ≥1 polyp removed in a piecemeal fashion regardless of the size Exclusion Criteria: Diagnosis of a CRC in the basal colonoscopy Subjects who neglect to follow-up Subjects who do not accept informed consent Subjects with high risk of perforation or complications due to sedation, including patients with comorbidities (ASA IV-V) Inadequate bowel preparation for colonoscopy (defined by Boston Bowel Preparation Score (BBPS): ≤ 5 total points; or 0-1 points in any of the 3 segments of the colon)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: WLE-NBI<br>Participants will be evaluated by same endoscopist, tandem colonoscopy. It consists of two revisions of the polypectomy scar using firstly High Definition White Light Endoscopy (WLE) and secondly Narrow Band Imaging. All suspected neoplasia will be classified macroscopically and resected and differentiated from both techniques. The rest of the gut will be inspected following conventional standards. | Device: WLE<br>* Evaluation of the polypectomy scar with High Definition White Light Endoscopy (WLE)<br>* Other names: High Definition colonoscopy with White Light Endoscopy (WLE);Device: NBI<br>* Evaluation of the polypectomy scar with Narrow Band Imaging (NBI, Evis Exera III, Olympus).<br>* Other names: Narrow Band Imaging;|
| Experimental: NBI-WLE<br>Participants will be evaluated by same endoscopist, tandem colonoscopy. It consists of two revisions of the polypectomy scar using firstly Narrow Band Imaging and secondly High Definition White Light Endoscopy (WLE). All suspected neoplasia will be classified macroscopically and resected and differentiated from both techniques. The rest of the gut will be inspected following conventional standards. | Device: WLE<br>* Evaluation of the polypectomy scar with High Definition White Light Endoscopy (WLE)<br>* Other names: High Definition colonoscopy with White Light Endoscopy (WLE);Device: NBI<br>* Evaluation of the polypectomy scar with Narrow Band Imaging (NBI, Evis Exera III, Olympus).<br>* Other names: Narrow Band Imaging;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of residual neoplastic tissue detected with both techniques (NBI versus WLE) | Efficacy of NBI in detecting residual neoplasia compared with WLE | less than 1 year after the basal colonoscopy | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of accurate detection of residual neoplastic tissue with morphologic features in both groups (NBI and WLE) compared with histopathology | Accuracy in detecting neoplastic tissue endoscopically compared with histopathology (gold standard) | less than 1 year after the basal colonoscopy | 
| Number of missed lesions on basal colonoscopy | Compare the number of missed lesions from the basal colonoscopy | less than 1 year after the basal colonoscopy | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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endoscopic mucosal resection, piecemeal polypectomy scar, colorectal neoplasms, Narrow Band Imaging, chromoendoscopy