Utility of serum CA19-9 in diagnosis of cholangiocarcinoma:In comparison with CEA

AIM:The diagnosis of cholangiocarcinoma is often difficult,making management approaches problematic.A reliableserum marker for cholangiocarcinoma would be a usefuldiagnostic test.The aims of our study were to evaluate theusefulness of a serum CA19-9 determination in the diagnosisof cholangiocarcinoma.METHODS:We prospectively measured serum CA19-9 andCEA concentrations in patients with cholangiocarcinoma(n=35),benign biliary diseases (n=92),and healthyindividuals (n=15).Serum CA19-9 and CEA concentrationswere measured by an immunoradiometric assay withoutknowledge of the clinical diagnosis.RESULTS:The sensitivity of a CA19-9 value >37 KU·L-1and a CEA value >22 μg·L-1in diagnosing cholangiocarcinomawere 77.14% and 68.57%,respectively.When comparedwith the benign biliary diseases group,the true negativerates of serum CA19-9 and CEA were 84.78% and 81.52%,respectively.The false positive rates of serum CA19-9 andCEA were 15.22% and 18.48%,whereas the accuracy ofserum CA19-9 and CEA were 82.68% and 77.95%,respectively.Serum CA19-9 and CEA concentrations weresignificantly elevated (P<0.001 and P<0.05) in patients withcholangiocarcinoma (290.31±5.34 KU·L-1and 36.46±18.03μg·L-1) compared with patients with benign biliary diseases(13.38±2.59 KU·L-1and 13.84±3.85 μg·L-1) and healthyindividuals (12.78±3.69 KU·L-1and 11.48±3.37 μg·L-1).In 15patients undergoing curative resection of cholangiocarcinoma,the mean serum CA19-9 concentration was decreased froma preoperative level of 286.41±4.36 KU·L-1to a postoperativelevel of 62.01±17.43 KU·L-1(P<0.001),and the mean serumCEA concentration from 39.41±24.35 μg·L1to 28.69±11.03μg·L-1(P<0.05).In patients with cholangiocarcinoma,however,no correlation was found between serum CEA andCA19-9 concentrations (r=0.036).CONCLUSION:These data suggest that the serum CA19-9determination is a useful addition to the available tests for thedifferential diagnosis of cholangiocarcinoma.Serum CA19-9 isan effective tumor marker in diagnosing cholangiocarcinoma,deciding whether the tumor has been radically resected andmonitoring effect of treatment.