Comparison of endoscopic ultrasonography with and without contrast enhancement for characterization of pancreatic tumors: a meta-analysis

Background and study aims Endoscopic ultrasonography (EUS) is a reliable and efficient modality for detecting pancreatic tumors; however, plain EUS (P-EUS) is limited with respect to characterization of pancreatic tumors. Recently, the use of contrast-enhanced harmonic EUS (CH-EUS) has increased, and its utility for characterization of pancreatic tumors has been reported. This meta-analysis compares the diagnostic ability of P-EUS with that of CH-EUS for characterization of pancreatic tumors. Methods A systematic meta-analysis of all potentially relevant articles in PubMed, the Cochrane library, and Google Scholar databases was performed. Fixed effects or random effects models were used to investigate pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio, with 95% confidence intervals (CIs). Results This meta-analysis included 719 patients who underwent CH-EUS and 723 who underwent P-EUS, from six eligible studies. The pooled estimates of sensitivity, specificity, and diagnostic odds ratio were 93% (95% CI, 0.90-0.95), 80% (95% CI, 0.75-0.85), and 57.9 (95% CI, 25.9-130), respectively, for CH-EUS, and 86% (95% CI, 0.82-0.89), 59% (95% CI, 0.52-0.65), and 8.3 (95% CI, 2.8-24.5) for P-EUS.The areas under the summary receiver operating characteristics curves for CH-EUS and P-EUS were 0.96 and 0.80, respectively. The diagnostic odds ratio for pancreatic cancer was 2.98 times higher on CH-EUS than on P-EUS (P = 0.03). Funnel plots demonstrated no publication bias. Conclusions This meta-analysis demonstrates that CH-EUS has higher diagnostic accuracy for pancreatic cancer than P-EUS, and is thus a valuable tool for characterization of pancreatic tumors.