CA 19-9 in serum and pancreatic juice: its role in the differential diagnosis of resectable pancreatic cancer from chronic pancreatitis.

The diagnostic role of serum and pancreatic juice CA 19-9 determination in discriminating surgically resectable pancreatic cancer from chronic pancreatitis was investigated. Only in about one third of cancer patients the serum assay was diagnostic versus subjects with chronic pancreatitis. None of 5 patients with 'early' pancreatic cancer had a diagnostic score [greater than 120 U/ml]. Conversely, the determination of CA 19-9 content in pure pancreatic juice, expressed as Units per microgram of protein, discriminated all the 15 patients with operable tumors, including those with early carcinoma, from subjects with chronic pancreatitis. The CA 19-9 assay of pancreatic juice is proposed as a reliable marker of cancer in those patients in whom the ERCP pattern is not definitive for malignancy.