Tissue Sampling through Endoscopic Ultrasound-Guided Fine Needle Aspiration versus Endoscopic Retrograde Cholangiopancreatographic Brushing Cytology Technique in Suspicious Malignant Biliary Stricture

BACKGROUND Differentiation of benign and malignant biliary strictures plays a pivotal role in managing biliary strictures. Brush cytology via endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) are two diagnostic methods. In the present study, we aimed to compare the accuracy of the results of EUS-FNA and ERCP-based sampling of biliary strictures. METHODS In a prospective study, between January 2019 and March 2020, patients with indeterminate biliary strictures who had no history of hepatobiliary surgery, opium usage, cancer of pancra- tobiliary system, and acute liver disease were selected. They underwent EUS and ERCP in the same session. They were followed up for 6 months, and the sensitivity, specificity, positive and negative predictive values, and accuracy of these imaging modalities were compared. RESULTS A total of 60 patients were enrolled. 28 lesions were located in the distal and 32 lesions in the proximal parts of the biliary tree. 55 malignant and 5 benign lesions were diagnosed. The sensitivity and accuracy of EUS-FNA and ERCP tissue sampling were 78.2% and 80.0% versus 50.9% and 55.0%, respectively (p = 0.024). The combination of both methods improved the sensitivity and accuracy to 85.5% and 86.7%, respectively. Regarding the location, EUS-FNA is superior to ERCP-brush cytology in diagnosing proximal lesions with sensitivity and specificity of 73.3% and 75.0% vs. 50.0% and 53.1%, respectively (p = 0.04). CONCLUSION EUS-FNA is superior to ERCP brushing in the diagnosis of indeterminate biliary strictures, particularly in distal lesions. Combining ERCP brushing and EUS-FNA improves the diagnosis accuracy.