Enhanced detection of cholangiocarcinoma with serum trypsinogen-2 in patients with severe bile duct strictures

Primary sclerosing cholangitis (PSC) is associated with a high risk of cholangiocarcinoma. Our aim was to evaluate the diagnostic value of trypsinogen-1, trypsinogen-2, tumour-associated trypsin inhibitor, human chorionic gonadotropin beta and trypsin-2-alpha(1)-antitrypsin for cholangiocarcinoma and to compare them with CA19-9 and CEA.

The study consisted of 84 patients with either PSC or cholangiocarcinoma or both referred for liver transplantation or other liver surgery. The serum concentrations were determined by time-resolved immunofluorometric assays.

Forty-six patients were transplanted due to PSC; in 3 of the explanted livers cholangiocarcinoma was found incidentally. All transplanted patients had severe biliary strictures together with cirrhosis or pre-cirrhosis. Twenty-nine of 38 patients with cholangiocarcinoma were candidates for intervention. In all, 8 patients had both PSC and cholangiocarcinoma. Receiver-operating characteristics curve analysis showed that serum trypsinogen-2 had the highest accuracy in differentiating between cholangiocarcinoma and PSC. The area under the curve (AUC) value was 0.804 for trypsinogen-2 and 0.613 for CA19-9. Serum trypsinogen-2 also showed the highest accuracy for differentiation between PSC and PSC with simultaneous cholangiocarcinoma with an AUC value of 0.759.

Our results suggest that serum trypsinogen-2 is a most useful marker for diagnosing patients with cholangiocarcinoma, and it is superior to serum CA19-9 and CEA.