CA 19-9 assay in differential diagnosis of pancreatic carcinoma from inflammatory pancreatic diseases.

Levels of a new carbohydrate antigen CA 19-9, which is a monosialoganglioside identified by a monoclonal antibody raised against colorectal carcinoma cells, were compared to carcinoembryonic antigen and tissue polypeptide antigen assays in 250 sera from patients with different pancreatic diseases including acute pancreatitis, chronic pancreatitis, and pancreatic cancer. All three tumoral markers were elevated at the onset of an acute pancreatic attack in a few patients. All but five patients with chronic pancreatitis displayed normal levels with each of the three markers; in two of these five cases an extraintestinal cancer was later discovered. CA 19-9 displayed higher sensitivity and predictive value of a negative result than the other two markers. The best operational characteristic of CA 19-9 was its high predictive value for a positive test which suggests a "ruling in" usage of it for pancreatic cancer diagnosis. CA 19-9 assay was of extreme value in disclosing both localized and metastatic pancreatic cancer while the other two markers were more often positive in the latter case. Of 71 cancer patients with positive markers, only four would have escaped a right diagnosis by assaying CA 19-9 alone.