The Use of Indigocarmine Spray Increases the Colonoscopic Detection Rate of Flat Adenomas and Large Sessile Hyperplastic Polyps

Abstract

Background: In Western populations, it is not clear whether indigocarmine (IC) spray during colonoscopy increases the detection of colorectal polyps. Methods: 500 patients were prospectively entered into this study. FAP and IBD patients were excluded. The patients were randomly allocated into 3 groups; A (n=200): A Japanese colonoscopist with expertise in IC spray performed chromo-colonoscopy with 0.2% IC solution sprayed onto the entire colon during scope withdrawal; B (n=200): Initial 100 patients (B-1), a Western colonoscopist with no previous experience of IC spray performed conventional colonoscopy, but with at least 10 minutes observation during colonoscopy withdrawal. In the next 100 patients (B-2), he performed chromo-colonoscopy with IC spray; C (n=100): Historical controls performed by the Western colonoscopist consecutively performed prior to the study. In all groups, all lesions were resected using standard techniques. Polyps were classified as pedunculated, sessile and flat. Histology was assessed by a single, blinded pathologist. Sex, age, indication, family history of colorectal cancer and past history of colorectal cancer were investigated as candidate confounding factors. Results: Mean numbers of all polyps (AP), neoplastic polyps (NP), flat neoplastic polyps (FNP) and large sessile hyperplastic polyps (LSHP) are shown in the table. In all types of polyps, there were significant differences between A and B-1, A and C, but there was no significant difference between A and B-2. Sex, age and indication were confounding factors in AP, NP and FNP. Family history was a confounding factor in NP, and past history in FNP. The negative binomial regression model was applied, because this model is a much better fit for the observed proportion rather than a Poisson regression model. Adjusting for confounding factors did not change the results Conclusion: IC spray significantly increases the detection rates of AP, NP, FNP and LSHP in a western population. Gastroenterologists can rapidly learn the technique.