The critical test is the abdominal scan – usually an ultrasound scan or CT scan is performed. An ultrasound scan will show the mass/tumour in the pancreas, the dilated bile duct system above the obstruction to its drainage and may be used to perform a diagnostic biopsy via a needle.
CA 19-9 is a cell surface antigen, an oligosaccharide (related to a blood group antigen), and this is expressed particularly in gastrointestinal cells and cancers derived from these cells and secreted into the blood stream where it is measurable; pancreatic cancer cells seem a rich source for CA 19-9. Serum levels of CA 19-9 more than 100 U/ml are rarely found in benign disease (although they may occur in some forms of obstructive jaundice producing a conflict in diagnostic accuracy if the cancer of the pancreas presents with jaundice) and can be used to diagnose and monitor disease activity in pancreatic cancer.
