Background and study aims: Strictures of the bile ducts due to malignant changes are difficult to distinguish from benign changes, particularly in patients with primary sclerosing cholangitis (PSC). The aim of this study was to evaluate diagnostic methods for malignancy in biliary strictures in conjunction with endoscopic retrograde cholangiopancreaticography (ERCP).
Patients and methods: Bile duct strictures were identified during ERCP in 57 patients, who were thus included in the present study. Brush samples from the strictures were taken for cytology and for evaluation of DNA content by flow cytometry. The tumor markers CA 19-9 and CEA were determined both in serum and bile fluid. Two independent radiologists evaluated all cholangiograms. The diagnostic sensitivity, specificity, and accuracy of each diagnostic method were evaluated separately and in combination.
Results: 32 patients were found to have malignant strictures and when the four methods: brush cytology, DNA analysis, serum CA 19-9 and serum CEA were combined, a diagnostic sensitivity of 88 % and specificity of 80 % were reached. Seven of the 20 patients with PSC were found also to suffer from cholangiocarcinoma, yielding a sensitivity and specificity of 100 % and 85 %, respectively. Analyses of CA 19-9 and CEA in bile fluid had no diagnostic significance.
Conclusion: An ERCP procedure with brush cytology, a DNA analysis, combined with serum analysis of CA 19-9 and CEA, can increase the possibility of distinguishing between malignant and benign biliary strictures, especially in PSC patients.