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

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

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

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.

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.

colon, cancer, screening, water exchange, air, method, polyp, adenoma, detection, rate, sedation, time, procedure

The intervention will be water exchange colonoscopy in patients who are randomized to have screening colonoscopy with water exchange colonoscopy.

The intervention will be colonoscopy using the traditional air method in patients who are randomized to have screening colonoscopy with air colonoscopy.

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.

Data collected when pathology is available, typically 3-10 days after the patient's procedure. Data is collected only once per patient.

Data collected when pathology is available, typically 3-10 days after the patient's procedure. Data is only collected once per patient.

This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length.

This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length.

This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length.

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.

This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length.

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.

This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length.

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.

This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length.

This will be collected at their procedure appointment which is expected to be 2 to 3 hours in length.

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 the time of their procedure appointment which is expected to be 2 to 3 hours in length

This will be collected at the time of their procedure appointment which is expected to be 2 to 3 hours in length

This will be collected at the time of their procedure appointment which is expected to be 2 to 3 hours in length

This will be collected at the time of their procedure appointment which is expected to be 2 to 3 hours in length

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)

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