Adjusted carbohydrate antigen 19-9. Correlation with histological grade in pancreatic adenocarcinoma.

BACKGROUND The serum level of carbohydrate antigen 19-9 (CA 19-9) depends on the tumor size and differentiation grade. Jaundice can cause an elevation of serum CA 19-9, although the nature of this interaction is not fully understood. PATIENTS AND METHODS This was a retrospective study of 26 patients with potentially resectable pancreatic adenocarcinoma. Serum CA 19-9 was correlated with the histological differentiation. CA 19-9 adjusted for serum bilirubin was determined and analyzed. RESULTS No correlation between CA 19-9 and histological differentiation was determined (p>0.05). The median adjusted CA 19-9 level was significantly lower (p=0.01) in patients with normal biliary excretion than those with bilirubin levels >2 mg/dL. CONCLUSION These data are consonant with the theory of a dual contribution to the serum CA 19-9 level from biliary obstruction and tumor cell synthesis.