Endoscopic retrograde wire-guided brush cytology for diagnosis of patients with malignant obstruction of the bile duct.

A brush was adapted for use over a guide wire to facilitate reliable acquisition of cytological specimens from tight and potentially malignant strictures encountered during ERCP. Cells collected in this manner were assessed for abnormalities indicative of cancer. We have called this technique endoscopic retrograde wire-guided brush cytology (ERWBC). Thirty-nine strictures (24 malignant, 15 benign) in 34 patients were brushed. There were no complications, and all specimens were adequate for evaluation. Sixty percent of patients with cancer were diagnosed by ERWBC. Sensitivity was highest for cholangiocarcinoma (100%), intermediate for pancreatic cancer (60%), and lowest for patients with biliary obstruction due to metastatic disease (22%). There were no false-positive results (specificity, 100%). The positive and negative predictive values were 100% and 58%, respectively, and accuracy for the test was 72%. Collection of cytological specimens using a brush with a wire guide is effective especially for diagnosis of cholangiocarcinoma. A positive result is sufficient evidence for malignancy, and other invasive diagnostic tests are unnecessary. We recommend ERWBC for brushing all strictures of unknown cause during ERCP in an effort to make a diagnosis of cancer.