[Diagnostic value of a new serum marker of human digestive cancer: the carbohydrate antigen 19.9; comparison with the carcinoembryonic antigen].

In order to evaluate its diagnostic value for digestive cancers, the carbohydrate antigen 19.9 (CA 19.9) was quantitated by radioimmunoassay in the serum of 102 patients suffering from malignant or non-malignant diseases of the digestive or pulmonary tract and of 20 healthy subjects. The carcinoembryonic antigen (CEA) was quantitated by enzyme-immunoassay in the same sera. No correlation was found between the CA 19.9 and the CEA levels. The sensitivity of the CA 19.9 test for the detection of digestive cancers (0.51) was not significantly higher than neither that of the CEA assay (0.46), nor that of the combined tests (0.59). Numerous false positive results were encountered in the CA 19.9 assay in pulmonary diseases and in non-cancerous liver diseases, especially cirrhosis. Its specificity (0.84) did not prove to be superior to that of CEA (0.90). Thus, in our experience, the clinical interest of serum CA 19.9 determination for the diagnosis of digestive cancers seems doubtful.