Prevention of bile duct cancer in primary sclerosing cholangitis.

Patients with primary sclerosing cholangitis (PSC) have a substantial predisposition to develop bile duct carcinoma. The mechanism is still unclear but the observation that patients with chronic Clonorchis sinensis infection are also prone to cholangiocarcinoma suggests a role for long standing inflammation. However, there is still no effective medical therapy which can halt the progression of the disease or prevent the development of cholangiocarcinoma. The only effective treatment for advanced PSC is orthotopic liver transplantation (OLT) which in the absence of cholangiocarcinoma has a 5 year survival of 89%. Patients with cholangiocarcinoma who undergo liver transplantation have a high risk of recurrence and a dramatically worse survival. Therefore, the identification of patients with a sufficient deterioration in liver function to warrant OLT before they develop cholangiocarcinoma remains a central goal in the management of PSC. Ideally, screening patients with PSC would allow the identification of those with dysplastic change in the biliary epithelia before the development of overt carcinoma. However, although serum tumour markers such as CA 19.9 and CEA can be of value in aiding the diagnosis of cholangiocarcinoma in PSC there is currently no evidence that they are helpful in identifying those patients with premalignant changes of the biliary epithelia who would benefit from surgery. There are also no genetic markers to identify those at particular risk of malignant change. A recent report has suggested that regular biliary cytology sampling to detect dysplasia can predict the development of cholangiocarcinoma. However, regular instrumentation of the biliary tree to obtain cytology is unlikely to be widely adopted.