The diagnosis ofcholangiocarcinoma is often dWkult, making management approaches problematic. A reliable serum tumor markerfor cholangiocarcinoma would be a useful additional diagnostic test. Previous studies have demonstrated that elevated serum concentrations of CA 19-9, a tumor-associated antigen, have good sensitivity and specificityfor cholangiocarcinoma in patients with primary sclerosing cholangitis. However, the value ofthis tumor markerfor cholangiocarcinoma unassociated with prima.ry sclerosing cholangitis is unclear. Thus. the aims of this study were to determine the usefulness of a serum CA 19-9 determination in the diagnosis ofde novo cholangiocarcinoma.
Methods: We measured serum CA 19-9 concentrations in patients with cholangiocarcinoma (n=25J, nonmalignant liver disease (n=30). and benign bile duct strictures (n=15). serum CA 19-9 concentrations were measured by a direct chemiluminometric technology.
Results: The sensitivity ofa CA 19-9 value> lOOUjml in diagnosing cholangiocarcinoma was 53%. When compared with the nonmalignant liver disease and the benign bile duct stricture groups, the true negative rales were 76% and 92%, respectively. Patients with unresectable cholangiDcarcinoma had significantly greater mean CA 19-9 concentrations compared to patients with resectable cholangiocarcinoma.
Conclusions: These data suggest that the serum CA 19-9 determination is a useful addition to the available testsfor the d!fferential diagnosis ojcholangiocarcinoma.