The Diagnostic Value of Brush Cytology on the Malignancy Detection Rate in Common Bile Duct Strictures before and after Dilation

Abstract

Background: Biliary strictures remain a major diagnostic challenge due to the difficulty in distinguishing benign from malignant lesions using clinical and radiological data alone. Although brush cytology via endoscopic retrograde cholangiopancreatography (ERCP) offers high specificity, its limited sensitivity leads to a significant rate of false-negative results, which may delay appropriate therapeutic intervention.

Objective: This study aimed to evaluate the diagnostic yield of brush cytology in detecting malignancy in common bile duct strictures before and after mechanical dilation.

Methods: A prospective diagnostic before-and-after study was conducted at Lattakia University Hospital between 2025 and 2026, enrolling 28 adult patients with common bile duct strictures undergoing ERCP.

Results: Malignancy was confirmed in 78.6% of patients. Cytology positivity increased from 42.9% before dilation to 50% after dilation, reaching 60.7% with combined samples. Sensitivity improved from 54.54% to 77.27% when combining both brushing results, while specificity remained 100%. Diagnostic accuracy rose from 64.28% to 82.14%. Significant associations were found with stricture location and dilation device type, favoring the Soehendra dilator. No significant associations were observed with age or gender. Complications were limited to mild pancreatitis (21.4%), with no bleeding or perforation.