Effectiveness of Instillation of Blue Water (Indigo Carmin®) for Colonoscopy

Overview

The colonoscopy is the reference examination for the diagnosis of neoplastic lesions in the colon and rectum. Mass screening assessment studies have shown that colonoscopic detection and removal of adenomas in patients selected through fecal occult blood test reduces colorectal cancer incidence and mortality. However, the literature has reported interval cancer cases or adenomas, probably "missed" by the colonoscopy. In theory, using coloured warm water could improve colon preparation by mobilizing the residual faeces, decreasing the colic spasm and increasing the visualization of the pit pattern. Preliminary American studies, led by Leung et al, have shown a very clear increase in the adenoma detection rate. The investigators' study involves 1 000 patients, treated in the Rhône-Alpes / Auvergne region. The patients present an indication for colonoscopy following a positive fecal occult blood test or symptoms or personal and family histories of pre-cancerous colonic lesions. They will be randomized into two study groups:one of both groups of study: Group 1: patients undergoing a colonoscopy wtih instillation of tepid water tinged with blue (Indigo Carmin®) Group 2: patients undergoing a standard colonoscopy with insufflation of air. The main objective is to show that the colonoscopy with blue water (Indigo Carmin®) enable detection of more lesions than standard colonoscopy with insufflation of air. The two techniques will be also compared in terms of tolerance, of duration of colonoscopy and type of detected lesions. In case of improved detection of colorectal lesions, the blue water instillation technique of could dramatically change gastroenterologists' practice by becoming the reference method. The expected clinical benefits are potential revealing of more neoplastic lesions and improvement in abdominal discomfort after colonoscopy.