Prospective Randomized Controlled Trial Comparing Water and Air Colonoscopy in a Community Based Setting

Study Overview
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Brief Summary
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The purpose of this study is to determine if screening colonoscopy performed on adults with the water exchange method, as opposed to the air method, will have a higher adenoma detection rate.

Detailed Description
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Screening colonoscopy with removal of pre-cancerous adenomas was recently shown to result in a 53% reduction in mortality from colon cancer. While this clearly validates the practice of screening colonoscopy, missed adenomas, especially in the proximal colon, defined as including cecum, ascending colon, and transverse colon, remains a concern. This was demonstrated in a study of 183 patients who underwent back-to-back colonoscopies. In this population the overall miss rate for adenomas was 24% with proximal adenomas missed more often (27%) than left colon adenomas (21%). Another study looked at 4192 patients in the SEER (Surveillance, Epidemiology, and End Results) Medicare database who developed interval cancers, that is colon cancer in a patient who had a colonoscopy done in the previous 6-36 months. These interval cancers were predominantly in the proximal colon (Proximal 68%, Distal 19.5%, rectum 10.4%, and unspecified 2.1%). This also suggests that pre-cancerous lesions are being missed in the proximal colon. As such a method that can increase proximal adenoma detection rate would be a welcome change. One such emerging technique which shows promise for improving adenoma detection rate is water colonoscopy. In one of the early studies employing the water method a trend towards a higher ADR in the water method group was recognized (37% vs. 26%). The observation prompted a retrospective analysis of 1178 cases of screening and surveillance colonoscopy performed by a single endoscopist at the Sacramento VAMC, which showed an overall ADR (presence of at least one adenoma) of 27% with air colonoscopy whereas that for the water method colonoscopy was 35% (p=0.007). In a subsequent combined analysis of two prospective RCT of air vs. water colonoscopy for screening and surveillance using scheduled unsedated colonoscopy [5] and on-demand sedation [6], more patients were found to have at least one diminutive adenoma in the proximal colon in the water method group than in the air group (28% vs. 14%, respectively, p=0.0298). Another quasi randomized study of screening patients performed at Phoenix VAMC using high definition equipment confirmed a significantly higher overall ADR with the water method (n=177) compared with the air method (n=191) (57% vs. 46%) (p=0.03). The odds of detecting an adenoma was 81% higher with the water method (OR 1.81; 95% CI: 1.12-2.90) and independent of age, body mass index (BMI), current smoking and alcohol use, withdrawal time & quality of bowel preparation. In the proximal colon ADR was significantly higher in patients examined with the water method than with air method (46% vs. 35%) (p=0.03), particularly for adenomas <10 mm in size (38% vs. 25%) (p=007). These encouraging preliminary data reflect the potential benefits of water method colonoscopy. Our current research question is whether this benefit is seen in a community based population as opposed to the VA population which is mostly male and Caucasian. The investigators plan to perform a prospective, randomized controlled trial comparing proximal adenoma detection rate between a water exchange colonoscopy group and an air colonoscopy group. The investigators intend to employ scheduled sedation, instead of on-demand sedation, to continue the current protocol in place at our institution. Patients in both the study arms will undergo a split bowel preparation before colonoscopy.

Official Title
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Prospective Randomized Controlled Trial Comparing Water Exchange Colonoscopy and Air Colonoscopy in a Community Based Setting

Conditions
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Tubular Adenoma, Colon Cancer, Hyperplastic Polyp

Intervention / Treatment
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* Other: Water Exchange Colonoscopy
* Other: Air Colonoscopy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥50 years Individuals able to provide informed consent Individuals presenting for average-risk colorectal cancer screening by colonoscopy Individuals presenting for surveillance of adenomatous/sessile serrated colon polyps as per the US multi-society taskforce on colorectal cancer Exclusion Criteria: Patients who decline to participate Prior partial or complete colectomy Patients with history of inflammatory bowel disease (ulcerative colitis or Crohn's disease) Patients with prior history of colorectal cancer Patients with history of screening colonoscopy within the past 10 years Patients with history of familial polyposis syndromes (Familial Adenomatous Polyposis, Lynch Syndrome)

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: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Water Exchange Colonoscopy<br>The intervention will be water exchange colonoscopy in patients who are randomized to have screening colonoscopy with water exchange colonoscopy. | Other: Water Exchange Colonoscopy<br>* We will turn off the air pump. The colonoscope will be inserted into the rectum and gently advanced. We will suction air pockets as scope is advanced towards the cecum. Water will be infused when encountering closed up lumen. All the infused water will be suctioned out. We will use all other techniques used with conventional air method as needed. For example abdominal pressure, shortening of scope to reduce looping, change of patient position etc. We will turn on air pump once cecum reached, or if unsuccessful with water method to open up a close lumen or to go past a tight turn. On withdrawal we will continue air insufflation as needed, and closely examine for polyps and remove all visualized polyps. If there is any residual fluid, it will be suctioned out as the scope is withdrawn.<br>|
| Active Comparator: Air colonoscopy<br>The intervention will be colonoscopy using the traditional air method in patients who are randomized to have screening colonoscopy with air colonoscopy. | Other: Air Colonoscopy<br>* Air will be infused into the colon during colonoscopy.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proximal Adenoma detection | Presence of adenoma detected anywhere between the cecum and the splenic flexure | Data collected when pathology is available, typically 3-10 days after the patient's procedure. Data is collected only once per patient. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total adenoma detection | Adenoma detection anywhere in the colon during colonoscopy. | Data collected when pathology is available, typically 3-10 days after the patient's procedure. Data is only collected once per patient. | 
| Sedation requirements | The amount of sedation required to complete the patient's colonoscopy. | This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length. | 
| Total procedure time | The total time it takes to complete colonoscopy. | This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length. | 
| Cecal intubation time | The time it takes to reach the cecum during colonoscopy. | This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length. | 
| Patient position change during procedure | The need for patient's position to be changed from left lateral to other positions, to enable advancement of the colonoscope forward. | This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length. | 
| Use of colonoscope stiffener during procedure | The need to stiffen the colonoscope to enable to forward movement of the scope during procedure | This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length. | 
| Abdominal pressure by assistant during procedure | Need for abdominal pressure by endoscopist's assistant during procedure to enable forward movement of colonoscope. | This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length. | 
| Length of colonoscope at time of cecal intubation | Assessment of length of the colonoscope inserted into the colon to reach the cecum. | This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length. | 
| Procedure-related pain score | Assessment of discomfort due to the procedure, as possible during procedure, and post procedure after recovery from sedation, being cognizant of limitations posed by sedation and attendant amnesia. | Data collected during and post procedure after recovery from sedation, which is usually within 1 hour post procedure | 
| Reason for air insufflation, and length of colon when air insufflation started, while performing water colonoscopy | Assessment of percentage of patient requiring air insufflation when water colon fails to open colonic lumen, and site of colon where this is most likely to happen. | This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length. | 
| Volume of water used during water colonoscopy | Assessment of volume of water introduced into the colon during procedure. | This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length. | 
| Patient perception regarding air and water colonoscopy | Assessment of patient's perception about the 2 methods of colonoscopy. | This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length. | 
| Advanced adenoma detection rate |  | Data collected when pathology is available, typically 3-10 days after the patient's procedure. Data is only collected once per patient | 
| Type of polypectomy (cold biopsy/cold snare/snare cautery/need for submucosal injection/need for clip placement) |  | This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length | 
| Bowel preparation quality by Boston Bowel Prep Scale |  | This will be collected at the time of their procedure appointment which is expected to be 2 to 3 hours in length | 
| Post procedure recovery time |  | This will be collected at the time of their procedure appointment which is expected to be 2 to 3 hours in length | 
| Serrated polyp detection rate |  | This will be collected at the time of their procedure appointment which is expected to be 2 to 3 hours in length | 
| Procedure time- morning versus afternoon |  | This will be collected at the time of their procedure appointment which is expected to be 2 to 3 hours in length | 
| Body Mass Index (BMI) |  | This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length | 
| Smoking history |  | This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length | 
| Alcohol consumption |  | This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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colon, cancer, screening, water exchange, air, method, polyp, adenoma, detection, rate, sedation, time, procedure