Diagnostic yield of EUS-guided FNA for malignant biliary stricture: a systematic review and meta-analysis

EUS-guided FNA (EUS-FNA) is increasingly being used for tissue diagnosis of extrahepatic biliary strictures. The aim of this study was to determine the diagnostic yield of EUS-FNA in malignant biliary strictures.A comprehensive literature review was carried out by 2 reviewers for studies evaluating the accuracy of EUS-FNA in biliary stricture. A meta-analysis was performed to determine the pooled estimates of sensitivity, specificity, likelihood ratios, and diagnostic odds ratio for EUS-FNA of extrahepatic biliary stricture. A Quality Assessment of Diagnostic Accuracy Studies questionnaire was used to assess the quality of the selected studies. Several sensitivity analyses were performed to assess the effect of the quality of the studies on the accuracy of the final results of the meta-analysis.Twenty studies involving 957 patients met inclusion criteria and were included in the meta-analysis. The pooled sensitivity and specificity of EUS-FNA for diagnosis of malignant biliary stricture were 80% (95% confidence interval [CI], 74%-86%), and 97% (95% CI, 94%-99%), respectively. The pooled positive likelihood ratio was 12.35 (95% CI, 7.37-20.72), and the negative likelihood ratio was 0.26 (95% CI, 0.18-0.38). The pooled diagnostic odds ratio for diagnosing a malignant biliary stricture was 70.53 (95% CI, 38.62-128.82). The area under the receiver-operating characteristic curve was 0.97. Sensitivity analyses showed that the quality of the included studies did not affect the accuracy of the final results of the meta-analysis.This meta-analysis demonstrates that EUS-FNA is sensitive and highly specific for diagnosing malignancy in biliary strictures. Further studies are needed to compare EUS--FNA with emerging methods including cholangioscopy-guided biopsy and laser endomicroscopy.