Diagnostic yield of methylene blue chromoendoscopy for detecting specialized intestinal metaplasia and dysplasia in Barrett's esophagus: a meta-analysis

Background: The reported yield of methylene-blue (MB) chromoendoscopy targeted biopsy in detecting specialized intestinal metaplasia (SIM) and, more importantly, dysplasia in patients with Barrett's esophagus (BE) has shown variable results. Objective: To perform a meta-analysis of published studies for assessment of the diagnostic yield of techniques of chromoendoscopy compared with conventional 4-quadrant random biopsy (RB) in detection of SIM and dysplasia in patients with BE. Design: A literature search of the MEDLINE, EMBASE, and the Cochrane Databases was performed, along with a search of PubMed and a manual search of cross-references of eligible articles. Data on yield of both modalities were extracted and analyzed to estimate weighted incremental yield (IY) and 95% CIs of MB over RB using a fixed-effects or random-effects model, as appropriate, based on whether homogeneity or heterogeneity, respectively, was indicated by Cochrane's Q χ ² test. Patients: A total of 450 patients with BE were reported in 9 studies included in the meta-analysis. Results: There was no significant IY with MB over RB for detection of SIM (IY 4%; 95% CI, -7% to 16%; 6 studies, n = 251), dysplasia (IY 9%; 95% CI, -1% to 20%; 9 studies, n = 450), and high-grade dysplasia and/or early cancer (IY 5%; 95% CI, -1% to 10%; 8 studies, n = 405). Limitations: Only data on MB were analyzed because of limited availability of data for other chromoendoscopy dyes, minor variations in inclusion and exclusion criteria, and the small sample size, and because differences in application technique could have led to an underestimation of the diagnostic yield of MB chromoendoscopy. Conclusion: The technique of MB chromoendoscopy has only a comparable yield with RB for the detection of SIM and dysplasia during endoscopic evaluation of patients with BE.