Comparison of CA 72-4 with CA 19-9 and carcinoembryonic antigen in the serodiagnostics of gastrointestinal malignancies.

Serum levels of the new tumor-associated marker CA 72-4 were measured in healthy controls (n = 64) and patients with benign (n = 410) or malignant (n = 199) gastrointestinal diseases. A cut-off limit of 4 U/ml was established. Tumor-indicating sensitivity was compared with that of the conventional markers carcinoembryonic antigen (CEA) and CA 19-9. In serodiagnostic evaluations CA 72-4 was clearly inferior to CA 19-9 in pancreatic carcinomas (22% versus 82%; all stages) and to CEA in colorectal cancer (32% versus 58%; all stages), with no appreciable diagnostic gain from combined determination. However, in gastric carcinoma CA 72-4 identified 59% of all patients (CA 19-9, 52%; CEA, 25%), and a combination of CA 72-4 and CA 19-9 detected as many as 70%. Positive results correlated roughly with tumor size. Compared with the other two tumor markers, CA 72-4 had a very high specificity (98%) in benign diseases of the gastrointestinal tract, including inflammatory processes, so that elevated serum levels of CA 72-4 should always be taken seriously.