A Prospective Study of the Yield of Endoscopic Ultrasound-Guided Fine-Needle Aspiration in Patients with Malignant-Appearing Biliary Strictures with Negative ERCP Bile Duct Brush Cytology

Abstract

The yield of ERCP brush cytology in suspected malignant biliary strictures is low. Patients with negative brush cytology may represent a subset of malignancies difficult to diagnose with endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Aim: To determine the yield of EUS-FNA in patients with negative brush cytology at initial ERCP. Methods: Between 11/01-7/03, a prospective study was performed to evaluate the yield of a novel Cytolong brush compared to the Geenen brush to detect malignancy in patients with biliary strictures. Patients with negative brush cytology who subsequently underwent EUS were identified. The location of the bile duct stricture (proximal, mid or distal bile duct) and the malignant tissue of origin was recorded. Results: 50 patients (26 M, mean age: 65 yrs, range: 27-83 yrs)with a malignant appearing bile duct stricture and negative ERCP brush cytology underwent EUS and form the basis for analysis. At EUS-FNA, a positive cancer diagnosis was made in 37 patients and negative in 13 patients. Of the 37 patients with positive EUS-FNA, 25 had pancreas adenocarcinoma, 7 hilar adenocarcinoma, 2 lymphoma, 1 cholangiocarcinoma, 1 metastatic breast carcinoma, and 1 neuroendocrine carcinoma. Of the 13 patients with negative EUS-FNA, 9 patients had a malignant diagnosis (7 pancreas adenocarcinoma, 1 lymphoma, 1 neuroendocrine carcinoma) and 4 patients had benign diagnosis (chronic pancreatitis) at time of surgery. Location of the bile duct strictures did not differ between the two groups: Positive EUS-FNA (65%distal, 22% proximal bile duct) as compared to Negative EUS-FNA (69% distal, 23% proximal). Sensitivity of EUS-FNA in patients with ERCP negative brush cytology was 80% (37/46), and the specificity was 100% (4/4) with a diagnostic accuracy of 82% (41/50). Conclusions: In patients with malignant-appearing bile duct strictures with negative brush cytology at ERCP, EUS-FNA is highly accurate in detecting malignancy. Location of the bile duct stricture did not influence accuracy of EUS-FNA.