Effect of brush rinse on the diagnostic accuracy of biliary stricture evaluation: A multicenter trial

Abstract

BACKGROUND: Brush cytology is the most commonly used technique for tissue acquisition during endoscopic retrograde cholangiopancreatography for the evaluation of biliary strictures. Nonetheless, brush cytology is limited by its low sensitivity due to insufficient cellular yield. OBJECTIVE: To evaluate the impact of the sheath-rinse technique on improving the cellularity yield. METHODS: A total of 112 patients with suspected malignant biliary strictures were enrolled at two tertiary centers in South Korea. The sample cellularity and diagnostic accuracy of brush-wash and sheath-rinse specimens were compared. RESULTS: A significantly increased number of total cell clusters per representative 20 × field was recorded in the sheath-rinse compared with the brush-wash specimens (median: 12 vs 3, P < 0.001). This trend persisted when large (> 50 cells) clusters (median: 8 vs 3, P < 0.001), medium (6-49 cells) (median: 7 vs 3, P < 0.001), and small (2-5 cells) clusters (median: 9 vs 3, P < 0.001) were evaluated. Diagnostic accuracy and sensitivity for differentiating malignancy were superior with sheath-rinsing than with the brush-wash method (72.3% vs 62.5%, P < 0.001 and 69.9% vs 59.2%, P < 0.001, respectively). CONCLUSIONS: Incorporating sheath-rinse specimens significantly improved the yield and diagnostic accuracy of biliary brush cytology. Sheath-rinsing should be integrated into routine clinical practice to improve diagnostic performance for biliary strictures. ©The Author(s) 2025. Published by Baishideng Publishing Group Inc. All rights reserved.