[CA19-9 has no value as a tumor marker in obstructive jaundice]

Abstract

In the differential diagnosis of pancreatic cancer, CA19-9 appears to be the most sensitive and specific marker currently in use. In the absence of jaundice and at levels greater than 1000 U/ml, the specificity is almost 100%. Levels higher than 1000 U/ml are very uncommon for benign diseases. We report a case of obstructive jaundice due to an impacted stone in the common bile duct with cholangitis, where a CA19-9 level of 61,800 U/ml prompted suspicion of a malignant cause. After treatment the CA19-9 returned to a normal level. One year postoperatively neither abdominal ultrasound nor CT-scan showed any sign of intraabdominal malignancy. Reviewing the literature, we conclude that even very high levels of CA19-9 in cases with obstructive jaundice can be caused by benign diseases. Unlike other tumour markers (alpha-foetoprotein, carcinoembryonic antigen), where exceedingly high levels are definitely caused by malignancy, high levels of CA19-9 can be caused by benign obstructive jaundice. In such cases CA19-9 is useless as a tumour marker. The biliary obstruction must be treated successfully and more diagnostic procedures or even laparotomy performed, to exclude malignancy or treat a benign disease.