Tissue polypeptide specific antigen (TPS), a marker for differentiation between pancreatic carcinoma and chronic pancreatitis: A comparative study with CA 19-9

Abstract

BACKGROUND. The value of serum tissue polypeptide specific antigen (TPS) as a complement to CA 19-9 in the detection of pancreatic carcinoma was determined prospectively. TPS and CA 19-9 levels obtained at the time of diagnosis in patients suspected of having chronic pancreatitis or pancreatic carcinoma were evaluated in receiver operating characteristic (ROC) curve analysis. METHODS. Serum TPS and CA 19-9 levels were measured by immunoassays in 122 subjects, 48 with pancreatic carcinoma and 74 with chronic pancreatitis. RESULTS. Elevated levels of CA 19-9 were detected preoperatively in 70% of pancreatic carcinoma patients and in 19% of chronic pancreatitis patients. Elevated levels of TPS were detected in 100% of patients with pancreatic carcinoma and in 22% of patients with chronic pancreatitis. The median levels of TPS and CA 19-9 for pancreatic carcinoma were significantly higher than those for chronic pancreatitis (P < 0.0001). Increasing the upper reference value of TPS allowed for better discrimination between chronic pancreatitis and pancreatic carcinoma. ROC curve analysis showed that the introduction of 200 U/L as a decision criterion for TPS did not reduce its sensitivity but significantly improved its specificity. At a specificity of 98% for TPS, discrimination between pancreatic carcinoma and chronic pancreatitis was found to be 97%. Increasing the upper reference level for CA 19-9 to attain a specificity of 98% decreased its sensitivity from 70% to 33%. CONCLUSIONS. At an elevated cut-off level for TPS (200 U/L), almost complete discrimination between pancreatic carcinoma and chronic pancreatitis was obtained. TPS will be more useful than CA 19-9 in the differential diagnosis of pancreatic carcinoma and chronic pancreatitis. (C) 2000 American Cancer Society.