Clinical Interpretation of Elevated CA 19-9 Levels in Obstructive Jaundice Following Benign and Malignant Pancreatobiliary Disease.

BACKGROUND/AIMS: Elevated carbohydrate antigen (CA) 19-9 level may be unable to differentiate between benign and malignant pancreatobiliary disease with obstructive jaundice. The study aims to determine the clinical interpretation and the diagnostic value of CA 19-9 level in pancreatobiliary diseases with coexistent obstructive jaundice.

METHODS

We retrospectively reviewed the data of 981 patients who underwent biliary drainage due to obstructive jaundice following pancreatobiliary disease at Sanggye Paik Hospital for 5 years. 114 patients with serial follow-up data for CA 19-9 level were included in this study (80 patients with malignancy and 34 patients with benign diseases). We compared the levels of CA 19-9 levels and the biochemical value before and after biliary drainage.

RESULTS

The rate of CA 19-9 elevation (>37 U/mL) was significantly different between the benign group and the malignant group (59% vs. 90%, p=0.001). Despite the decrease in serum bilirubin after biliary drainage, CA 19-9 levels remained elevated in 12% of patients in the benign group and in 63% of patients in the malignant group (p<0.001). Finally, 12% of patients in the benign group turned out to have malignant disease. A receiver operating characteristic analysis provided a cut-off value of 38 U/mL for differentiating benign disease from malignant disease after biliary drainage (area under curve, 0.787; 95% confidence interval, 0.703 to 0.871; sensitivity, 62%; specificity, 88%).

CONCLUSIONS

This study suggested that we should consider the possibility of malignant causes if the CA 19-9 levels remain high or are more than 38 U/mL after resolution of biliary obstruction.