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

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

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.

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.

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.

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

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.

0.008% indigo carmine in water is used as a surface contrast agent to enhance visualization of diminutive polyps (adenoma) during screening colonoscopy

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.

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

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.

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

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.

Leung JW, Ransibrahmanakul K, Toomsen L, Mann SK, Siao-Salera R, Leung FW. The water method combined with chromoendoscopy enhances adenoma detection. J Interv Gastroenterol. 2011 Apr;1(2):53-58. doi: 10.4161/jig.1.2.16827.

Leung FW, Leung JW, Siao-Salera RM, Mann SK, Jackson G. The water method significantly enhances detection of diminutive lesions (adenoma and hyperplastic polyp combined) in the proximal colon in screening colonoscopy - data derived from two RCT in US veterans. J Interv Gastroenterol. 2011 Apr;1(2):48-52. doi: 10.4161/jig.1.2.16826.

Leung JW, Do LD, Siao-Salera RM, Ngo C, Parikh DA, Mann SK, Leung FW. Retrospective analysis showing the water method increased adenoma detection rate - a hypothesis generating observation. J Interv Gastroenterol. 2011 Jan;1(1):3-7. doi: 10.4161/jig.1.1.14585.

Leung J, Mann S, Siao-Salera R, Ransibrahmanakul K, Lim B, Canete W, Samson L, Gutierrez R, Leung FW. A randomized, controlled trial to confirm the beneficial effects of the water method on U.S. veterans undergoing colonoscopy with the option of on-demand sedation. Gastrointest Endosc. 2011 Jan;73(1):103-10. doi: 10.1016/j.gie.2010.09.020.

Leung JW, Mann SK, Siao-Salera R, Ransibrahmanakul K, Lim B, Cabrera H, Canete W, Barredo P, Gutierrez R, Leung FW. A randomized, controlled comparison of warm water infusion in lieu of air insufflation versus air insufflation for aiding colonoscopy insertion in sedated patients undergoing colorectal cancer screening and surveillance. Gastrointest Endosc. 2009 Sep;70(3):505-10. doi: 10.1016/j.gie.2008.12.253. Epub 2009 Jun 24.

Leung JW, Thai A, Yen A, Ward G, Abramyan O, Lee J, Smith B, Leung F. Magnetic endoscope imaging (ScopeGuide) elucidates the mechanism of action of the pain-alleviating impact of water exchange colonoscopy - attenuation of loop formation. J Interv Gastroenterol. 2012 Jul;2(3):142-146. doi: 10.4161/jig.23738. Epub 2012 Jul 1.

Yen AW, Leung JW, Leung FW. A new method for screening and surveillance colonoscopy: Combined water-exchange and cap-assisted colonoscopy. J Interv Gastroenterol. 2012 Jul;2(3):114-119. doi: 10.4161/jig.23730. Epub 2012 Jul 1.

Yen AW, Leung JW, Leung FW. A novel method with significant impact on adenoma detection: combined water-exchange and cap-assisted colonoscopy. Gastrointest Endosc. 2013 Jun;77(6):944-8. doi: 10.1016/j.gie.2013.01.011. Epub 2013 Mar 6.

Leung JW, Siao-Salera R, Abramyan O, Mann SK, Ward G, Yen A, Gutierrez R, Leung FW. Impact of water exchange colonoscopy on serum sodium and potassium levels: an observational study. Dig Dis Sci. 2014 Mar;59(3):653-7. doi: 10.1007/s10620-013-2934-0. Epub 2013 Nov 20.

Ngo C, Leung JW, Mann SK, Terrado C, Bowlus C, Ingram D, Leung FW. Interim report of a randomized cross-over study comparing clinical performance of novice trainee endoscopists using conventional air insufflation versus warm water infusion colonoscopy. J Interv Gastroenterol. 2012 Jul;2(3):135-139. doi: 10.4161/jig.23736. Epub 2012 Jul 1.

Leung J, Mann S, Siao-Salera R, Ngo C, McCreery R, Canete W, Leung F. Indigocarmine added to the water exchange method enhances adenoma detection - a RCT. J Interv Gastroenterol. 2012 Jul;2(3):106-111. doi: 10.4161/jig.23728. Epub 2012 Jul 1.

Leung FW, Pan Y, Mann SK, Leung JW, Siao-Salera RM, Jackson G. The water exchange method and difficult colonoscopy. J Interv Gastroenterol. 2012 Jul;2(3):103-105. doi: 10.4161/jig.23727. Epub 2012 Jul 1. No abstract available.

Leung F, Harker J, Leung J, Siao-Salera R, Mann S, Ramirez F, Friedland S, Amato A, Radaelli F, Paggi S, Terruzzi V, Hsieh Y. Removal of infused water predominantly during insertion (water exchange) is consistently associated with a greater reduction of pain score - review of randomized controlled trials (RCTs) of water method colonoscopy. J Interv Gastroenterol. 2011 Jul;1(3):114-120. doi: 10.4161/jig.1.3.18510. Epub 2011 Jul 1.