Biochemical profile of bile fluid in patients with malignant cholestasis in comparison with cholestasis due to gall stone.

Chlangiocarcinomas arise from the epithelial cells of the bile ducts. These cancers are highly lethal because mostly are locally advanced at presentation. Due to the specific anatomy of the disease, access to the tumor for tissue sampling is difficult and imaging methods such as endoscopic retrograde chollangiopanereatography (ERCP) with brushing have less than 50% yield at the best (1, 2). Cholangiography performed by ERCP or via a percutaneous approach is the gold standard for defining the location and extension of suspected bile duct lesion but up to one third of the patients with symptoms and cholangiogram suggestive of a bile duct malignancy will have either benign fibrosing disease or another malignancy with metastases that obstruct the bile ducts. Tissue diagnosis can be obtained by a variety of means in patients suspected of having a hilar malignancy but is often difficult to obtain. Endoscopic brush cytology has a limited sensitivity and the addition of endoscopic biopsy of the malignant strictures increases this sensitivity up to 60%. Therefore diagnostic methods using biochemical and molecular markers which are present in the bile fluid and have a higher sensitivity for the diagnosis of cholangiocarcinoma may be used for this purpose. In the recent years, it has been attempted to differentiate malignant from non-malignant extrahepatic cholestasis by using biochemical and cytologic markers of the bile fluid. O’Mahony et al. studied molecular mutations in the bile samples of patients with pancreatic and biliary cancers (3). Serum levels of cancer antigen CA19.9 are widely used for detecting cholangiocarcinoma but optimal cutoff value that best discriminates between benign or malignant biliary disease is influenced by the presence of cholangitis or cholestasis (4). In other studies, it has been tried to differentiate between malignant and non-malignant biliary disease using FNA assisted cytologic evaluation (5, 6). This study was designed to evaluate the diagnostic value of biochemical profile and tumor marker level of bile fluid in patients with malignant cholestasis in comparison with cholestasis due to gall stone.