Background: Earlier studies suggest that the free beta-subunit of human chorionic gonadotropin (hCGbeta) may be a useful tumour marker for gastrointestinal cancers. Our aim was to investigate hCGbeta in serum in gastrointestinal diseases in comparison with CA 19-9 and carcinoembryonic antigen (CEA).
Patients and methods: The serum concentrations of hCGbeta, CA 19-9 and CEA were measured from 142 patients with malignant and 178 with benign gastrointestinal diseases. The diagnostic accuracies of the markers were compared and a diagnostic algorithm was established with logistic regression (LR) analysis.
Results: The hCGbeta serum level was elevated most frequently in bile duct (56%), pancreatic (45%) and gastric cancer (41%). In benign diseases, hCGbeta concentration was elevated in 10% of the patients. In an LR model each marker provided independent diagnostic information and the probability of cancer was calculated. It was applied as a diagnostic algorithm providing better accuracy than the markers alone. In receiver operating characteristic (ROC) curve analysis the area under the curve (AUC) value of the algorithm was significantly higher than the AUC values of CA 19-9, CEA, or hCGbeta (p=0.009-0.049).
Conclusion: Serum hCGbeta, CA 19-9 and CEA provide additive diagnostic information in gastrointestinal malignancies and the use of an algorithm established by LR analysis improves diagnostic accuracy.