Study of Narrow Band Imaging in the Characterization of Serrated Lesions

Study Overview
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Brief Summary
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This study is designed to evaluate the utility of Narrow Band Imaging (NBI) compared with High Definition White Light colonoscopy (WLE) in subjects with serrated lesions who do not fulfill the diagnostic criteria of Serrated Polyposis Syndrome (SPS).

Detailed Description
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Colorectal cancer (CRC) is the second leading cause of cancer death in western countries. Conventional polyps were considered the precursor lesions of all cases of sporadic colon cancer. Recently, serrated lesions and especially the Sessile Serrated Adenoma (SSA), are responsible of interval CRC between 20% to 35% of all CRC cases. These polyps are difficult to identify at endoscopy because they are located in the right colon, they are sessile or flat morphology and are pale color with mucus capping. According to the WHO, SPS is defined with one of the following criteria: (1) at least 5 serrated polyps proximal to the sigmoid colon, 2 of which are greater than 10 mm in diameter; (2) any number of serrated polyps occurring proximal to the sigmoid colon in an individual who has a first-degree relative with serrated polyposis; or (3) more than 20 serrated polyps of any size distributed throughout the colon. Therefore, patients with SPS are considered to be at increased risk of CRC. Considering the substantial risk of polyp recurrence, it is mandatory to follow up an annual surveillance. Narrow-Band Imaging (NBI, Olympus) selectively uses certain wavelengths of the visible light leading to a shift in the excitation spectrum towards blue light. Blood vessels will appear dark, allowing an improved visibility and identification of the surface and vascular structures. In contrast to conventional chromoendoscopy, it is easily activated by pressing a button on the endoscope. A pilot study in patients with SPS showed significantly lower polyp miss rate with NBI compared with WLE. Furthermore, 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 chromoendoscopy or NBI in patients with SPS (strong recommendation, low quality evidence). The hypothesis is that NBI could improve the detection rate of serrated polyps compared with WLE in patients who do not accomplish the SPS criteria. The investigators will perform a randomised, cross-over trial of tandem colonoscopy using NBI and WLE. The main goal is to compare the rate of detected polyps between both techniques and, if it is necessary, reassessing the diagnosis for an appropriate surveillance interval.

Official Title
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Randomised Tandem Colonoscopy of Narrow Band Imaging (NBI) and White Light Endoscopy in Patients With Serrated Lesions

Conditions
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Serrated Polyps, Sessile Serrated Adenoma, Colorectal Neoplasms

Intervention / Treatment
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* Device: NBI
* Device: WLE


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients over 50 years old who accept CRC screening colonoscopy Patients with a basal colonoscopy findings: ≥1 serrated polyps proximal to the sigmoid colon, which are greater than ≥10mm in diameter; or ≥3 serrated polyps proximal to the sigmoid colon Exclusion Criteria: Diagnosis of a CRC in the basal colonoscopy Subjects with other types of histology polyps 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: 50 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, back-to-back tandem colonoscopy. It consists of two withdrawal from the cecum to sigmoid colon using firstly High Definition White Light Endoscopy (WLE) and secondly Narrow Band Imaging (NBI). All detected polyps will be classified macroscopically and resected in each withdrawal. | Device: NBI<br>* Withdrawal from cecum to sigmoid colon with Narrow Band Imaging (NBI, Evis Exera III, Olympus)<br>* Other names: Narrow Band Imaging;Device: WLE<br>* Withdrawal from cecum to sigmoid colon with High Definition White Light Endoscopy (WLE)<br>* Other names: High Definition White Light Endoscopy;|
| Experimental: NBI-WLE<br>Participants will be evaluated by same endoscopist, back-to-back tandem colonoscopy. It consists of two withdrawal from the cecum to sigmoid colon using firstly Narrow Band Imaging (NBI) and secondly High Definition White Light Endoscopy (WLE). All detected polyps will be classified macroscopically and resected in each withdrawal. | Device: NBI<br>* Withdrawal from cecum to sigmoid colon with Narrow Band Imaging (NBI, Evis Exera III, Olympus)<br>* Other names: Narrow Band Imaging;Device: WLE<br>* Withdrawal from cecum to sigmoid colon with High Definition White Light Endoscopy (WLE)<br>* Other names: High Definition White Light Endoscopy;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of polyps detected with both techniques (NBI versus WLE) | Efficacy of NBI in detecting serrated polyps compared with WLE | Less than 1 year after the basal colonoscopy | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of new patients who accomplish the SPS criteria |  | Less than 1 year after the basal colonoscopy | 
| Number of missed lesions on basal colonoscopy | Compare the number of missed lesions on the index examination based on the colonoscopy findings (NBI and WLE) | Less than 1 year after the basal colonoscopy | 
| Number of accurate detection of adenomas with morphologic features with both groups (NBI and WLE) compared to histopathology | Accuracy in detecting adenomas endoscopically compared with histopathology (gold standard) | 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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Serrated lesion, sessile serrated adenoma, Narrow Band Imaging, Colonoscopy, colorectal neoplasms