Comparative Efficacy of Water & Indigo Carmine vs. Water or Air Method on Adenoma Detection Rate (ADR) - a Randomized Controlled Trial (RCT)

Study Overview
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Brief Summary
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Adenoma detection rate (ADR) is a quality indicator of colonoscopy performed for colorectal cancer screening. Population studies have shown that traditional air colonoscopy fails to eliminate post screening colonoscopy cancers or cancer mortality in the proximal colon. The investigators aim to establish the superior effectiveness of combining chromoendoscopy with the water exchange method in detecting more proximal diminutive adenomas during screening colonoscopy in sedated Veterans. An improved adenoma detection rate associated with optical colonoscopy will minimize the risk of missed lesions. The improvement may translate into a remedy for the limitations of screening colonoscopy in the proximal colon, e.g. a higher adenoma detection rate may minimize the burden of post screening colonoscopy interval colorectal cancers among the veteran population.

Detailed Description
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Design: Prospective, single center, patient blinded, randomized controlled trial Methods: Colonoscopy with traditional air insufflation, water exchange or water exchange plus indigocarmine to aid insertion of colonoscope; split dose bowel preparation; all patients will receive sedation; assessment of serum electrolytes level before and after colonoscopy Control method: Traditional air insufflation method. Study methods: Water exchange method. Water method combined with chromoendoscopy (0.008% indigo carmine). Population to be studied Veterans between age 50 and 75 referred for first time screening colonoscopy Unit(s) of analysis Primary outcome: overall adenoma detection rate. Secondary outcomes: patient demographic variable and procedure related measures. Sampling strategy: all Veterans referred for screening colonoscopy will be offered enrollment in the study. Sample size calculation. A total of 480 subjects will be recruited and randomized with 160 in each group. 5. Subject recruitment: patients referred for screening colonoscopy come from three sources. 6. Description of base population and groups to be studied and method of randomization. Veterans between age 50 and 75 referred for first time screening colonoscopy. After informed consent, assignment to control or study arm based on computer generated random number codes stored in pre-arranged opaque envelopes.

Official Title
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Comparative Efficacy of Water & Indigo Carmine vs Water or Air Method

Conditions
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Colorectal Neoplasms

Intervention / Treatment
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* Drug: Indigo carmine
* Procedure: water (exchange) method
* Procedure: water (exchange) plus dye method
* Procedure: air method


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: asymptomatic Veterans scheduled for first time screening colonoscopy and agree to be randomized will be enrolled. Exclusion Criteria: patients who decline to be randomized, non screening cases.

Ages Eligible for Study
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Minimum Age: 45 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: water (exchange) method<br>Residual pocket of air will be suctioned. Water is infused using a peristaltic pump to facilitate scope advancement until the cecum is reached. Dirty water will be suctioned and clean water is infused. Air will not be insufflated until the cecum is reached. Residual water is suctioned and air insufflated on scope withdrawal to facilitate biopsy and removal of lesions. | Procedure: water (exchange) method<br>* Residual pocket of air will be suctioned. Water is infused using a peristaltic pump to facilitate scope advancement until the cecum is reached. Dirty water will be suctioned and clean water is infused. Air will not be insufflated until the cecum is reached. Residual water is suctioned and air insufflated on scope withdrawal to facilitate biopsy and removal of lesions.<br>|
| Experimental: water (exchange) plus dye method<br>Residual pocket of air will be suctioned. Water with 0.008% indigocarmine is infused using a peristaltic pump to facilitate scope advancement until the cecum is reached. Dirty water will be suctioned and clean water is infused. Air will not be insufflated until the cecum is reached. Residual water is suctioned and air insufflated on scope withdrawal to facilitate biopsy and removal of lesions | Drug: Indigo carmine<br>* 0.008% indigo carmine in water is used as a surface contrast agent to enhance visualization of diminutive polyps (adenoma) during screening colonoscopy<br>Procedure: water (exchange) plus dye method<br>* Residual pocket of air will be suctioned. Water with 0.008% indigocarmine is infused using a peristaltic pump to facilitate scope advancement until the cecum is reached. Dirty water will be suctioned and clean water is infused. Air will not be insufflated until the cecum is reached. Residual water is suctioned and air insufflated on scope withdrawal to facilitate biopsy and removal of lesions<br>|
| Active Comparator: air method<br>The colonoscope is inserted gently and advanced slowly using minimal air insufflation, if necessary, the assistant will provide abdominal compression or the patient's position will be changed to facilitate scope passage. The scope is inserted until the cecum is reached. Air is insufflated on scope withdrawal for visualization and water irrigation is used to remove any adherent feces covering the mucosa. Biopsy or polypectomy is performed where indicated. | Procedure: air method<br>* The colonoscope is inserted gently and advanced slowly using minimal air insufflation, if necessary, the assistant will provide abdominal compression or the patient's position will be changed to facilitate scope passage. The scope is inserted until the cecum is reached. Air is insufflated on scope withdrawal for visualization and water irrigation is used to remove any adherent feces covering the mucosa. Biopsy or polypectomy is performed where indicated.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With Detected Proximal Diminutive (<10 mm) Adenoma Detection Rate | Proximal diminutive adenoma detection rate (ADR) in screening colonoscopy performed with the unusual air method, versus the water (exchange) method and with dye added to the water (exchange) method | 36 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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adenoma detection, screening colonoscopy, water exchange method, chromoendoscopy