Comparative Efficacy of Water & Indigo Carmine vs. Water or Air Method on Adenoma Detection Rate (ADR) - a Randomized Controlled Trial (RCT)
Condition: Colorectal Neoplasms
MeSH terms: Colorectal Neoplasms
Study type: Interventional
Phase: Phase 4

Summary: 
      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: 
      1. Design: Prospective, single center, patient blinded, randomized controlled trial

        2. 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

             1. Control method: Traditional air insufflation method.

             2. Study methods:

                  -  Water exchange method.

                  -  Water method combined with chromoendoscopy (0.008% indigo carmine).

        3. Population to be studied Veterans between age 50 and 75 referred for first time
           screening colonoscopy

        4. Unit(s) of analysis

             1. Primary outcome: overall adenoma detection rate.

             2. Secondary outcomes: patient demographic variable and procedure related measures.

        5. Sampling strategy: all Veterans referred for screening colonoscopy will be offered
           enrollment in the study.

             1. 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.
    

Intervention name(s): Indigo carmine; water (exchange) method; water (exchange) plus dye method; air method
Intervention type(s): Drug; Procedure; Procedure; Procedure
Intervention description(s): 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.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: adenoma detection; screening colonoscopy; water exchange method; chromoendoscopy