Diagnostic role of serum interleukin 6 and CA 19-9 in patients with cholangiocarcinoma.

Background/aims: Cholangiocarcinoma is particularly common in Northeastern Thailand where the liver fluke, O. viverrini, is endemic. Currently there is no sensitive and specific tumor marker for the diagnosis of this cancer. The aim of this study was to investigate the accuracy of carbohydrate antigen 19-9 and interleukin-6 in the diagnosis of cholangiocarcinoma. The first marker represents the commonly used serum marker in cholangiocarcinoma and the second marker is a multi-functional cytokine associated with cancer development.

Methodology: The serum concentrations of carbohydrate antigen 19-9 and interleukin-6 were simultaneously determined in 45 patients with cholangiocarcinoma, 15 with hepatocellular carcinoma, 15 with metastatic liver cancers, 10 with benign biliary disease and 10 healthy controls.

Results: The sensitivity of carbohydrate antigen 19-9 value (> or = 37 U/mL) in diagnosing cholangiocarcinoma was 64.4%, while its specificity was 100% and 56.7% when compared with benign biliary disease and other liver cancers, respectively. The sensitivity and specificity of detectable interleukin-6 (> or = 0.18 ng/mL) for differentiating between cholangiocarcinoma and benign biliary disease was 71.1% and 90%, respectively, whereas the specificity for differentiating cholangiocarcinoma from other liver cancers was 26.7%. When higher concentrations of either carbohydrate antigen 19-9 (> or = 100 U/mL) or interleukin-6 (> or = 50 pg/mL) were used as the cut-off points, they provided additional diagnostic sensitivity and accuracy in differentiating between cholangiocarcinoma and other liver cancers to 80% and 76%, respectively.

Conclusions: The combined assays of both serum carbohydrate antigen 19-9 and interleukin-6 could be useful in diagnosing cholangiocarcinoma, particularly in populations where this cancer is prevalent.