The clinical applications of serum tumor markers in gastroenterology

Serum tumors markers tests have five potential uses; the value of a given tests depends on its sensitivity and specificity. As a rule tumor markers have no use as screening tests except for alpha-fetoprotein in hepatocarcinoma which value has been established, for monitoring treatment and for detecting relapse. On the other hand the highest value for carcino-embryonic antigen tests lies on the early detection of colonic cancer relapse. Ca 19-9 assay has a high sensitivity and specificity in diagnosis of pancreatic cancer and a high predictive value in unresectable disease. Low serum Testosterone/dihydrotestosterone ratio is useful in diagnosis pancreatic carcinoma. There is no useful marker for diagnosis of gastric cancer.