Evaluation of CEA, CA 19-9, CA-50, CA-195, and TATI with special reference to pancreatic disorders

The tumor markers CEA, CA 19-9, CA-50, CA-195, and TATI were analyzed in patients with pancreatic diseases as well as disorders in the upper quadrant of the abdomen. Two different methods for CA-50, namely CA-50 IRMA and CA-50 DELFIA, which are based on the same monoclonal antibody, were used. The sensitivities, specificities, and predictive values of positive and negative results were calculated at one, three, and ten multiples of the upper reference value ("cutoff") for each method. All the tumor markers except TATI had sensitivities exceeding 90% at one cutoff level, but CEA had low specificity. Poor sensitivities were observed for CEA and TATI at three cutoff levels, whereas CA 19-9, CA-50, and CA-195 had sensitivities and specificities greater than 80%. The sensitivities of these tumor markers decreased at 10 cutoff levels, although the specificities exceeded 95%. The predictive values of positive and negative results were also evaluated at these three cutoff levels. High scores were observed at three cutoff levels. Examined together with the sensitivity and specificity, the evaluation at three cutoff levels indicated that CA 19-9, CA-50, and CA-195 can be used in the diagnostic arsenal for the detection of cancer of the exocrine pancreas in symptomatic patients, and in the differential diagnosis between pancreatic cancer and chronic pancreatitis. Although CA-50 IRMA and CA-50 DELFIA are based on the same monoclonal antibody, there were substantial differences in the levels of CA-50 in a lot of the patients when samples were analyzed by the two methods. These differences were shown to be methodological, and they affected the test evaluations to some extent.