Introduction Early adenoma detection is shown to reduce mortality from colorectal cancers. Advances in endoscopy are aimed at improving adenoma detection. Contrast enhancement using dye spray is reported to improve the detection of subtle mucosal changes. We aim to perform a meta-analysis to look at the effect of chromoendoscopy on adenoma detection in the colon.
Methods Various electronic databases were searched for articles reporting on detection of polyps during colonoscopy comparing standard while light endoscopy and chromoendoscopy. The pooled mean differences in total number of adenomatous polyps detected, number of right and left sided polyps, advanced and flat adenomas, total number of polyps and number of < 5mm polyps detected was calculated. A fixed effects model was used unless there was significant heterogeneity. Publication bias was assessed using Funnel plots and Egger’s test and heterogeneity was assessed using Cochran’s Q and the I2 test.
Results 3714 number of patients from 14 studies were included in the analysis. 7 studies were randomised controlled trials and 7 had a tandem colonoscopy study design. Chromoendoscopy detected significantly higher number of adenomas, advanced adenomas, right and left sided adenomas (Table 1). A significantly higher number for hyperplastic and small (< 5mm) polyps were detected by chromoendoscopy but no differences were noted for detection of flat adenomas. A random effects model was used because there was significant heterogeneity between the studies. There was some publication bias noted on the funnel plot with fewer number of smaller negative studies included. Sensitivity analysis for publication bias using the trim and fill method which did not change the statistical significance of the pooled analysis.
Conclusion Conclusions: Chromoendoscopy improves detection rate of adenomatous polyps compared to conventional white light endoscopy. This seems greater for advanced as well as right sided adenomas, but significantly higher number of hyperplastic and small (< 5 mm) polyps were detected by chromoendoscopy. Future work needs to focus on the cost effectiveness of chromoendoscopy taking into account the increased time and cost of chromoendoscopy and long term outcomes like reduction in colorectal cancer rates between chromoendoscopic and conventional colonoscopy surveillance.
Disclosure of Interest None Declared.
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