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.