Comparative effectiveness of biliary brush cytology and intraductal biopsy for detection of malignant biliary strictures: a systematic review and meta-analysis

Background Evaluation of indeterminate biliary strictures typically involves collection and analysis of tissue or cells. Brush cytology and intraductal biopsies that are routinely performed during ERCP to assess malignant-appearing biliary strictures are limited by relatively low sensitivity. Objective To study the comparative effectiveness of brushings for cytology and intraductal biopsies in the etiology of biliary strictures. Design Meta-analysis. Setting Referral center. Patients PUBMED and Embase databases were reviewed for studies published to April 2014 where diagnostic correlation of histology was available. Intervention Database and review of study findings. Main Outcome Measurements Sensitivity and specificity. Results The pooled sensitivity and specificity of brushings for the diagnosis of malignant biliary strictures was 45% (95% confidence interval [CI], 40%-50%) and 99% (95% CI, 98%-100%), respectively. The pooled diagnostic odds ratio to detect malignant biliary strictures was 33.43 (95% CI, 14.29-78.24). For intraductal biopsies, the pooled sensitivity and specificity were 48.1% (95% CI, 42.8%-53.4%) and 99.2% (95% CI, 97.6%-99.8%), respectively. The pooled diagnostic odds ratio to detect malignant biliary strictures was 43.18 (95% CI, 19.39-95.83). A combination of both modalities only modestly increased the sensitivity (59.4%; 95% CI, 53.7%-64.8%) with a specificity of 100% (95% CI, 98.8%-100.0%). The Begg-Mazumdar and Egger tests indicated a low potential for publication bias. Limitations Inclusion of low-quality studies. Conclusion Our study suggests that both brushings and biopsy are comparable and have limited sensitivity for the diagnosis of malignant biliary strictures. A combination of both only modestly increases the sensitivity.