Clinical experience with the tumor marker Ca 19-9 in an unselected group of more than 300 tumor patients.

: Since March, 1983, in vitro tests for the quantitative determination of the tumor-associated antigen Ca 19-9 (carbohydrate antigen 19-9) were performed in more than 300 patients with confirmed tumors. These tests had as a goal determination of the diagnostic value of this new potential tumor marker Ca 19-9 with regard to specificity and sensitivity of malignant growths in the gastrointestinal tract, breast, and lung. The applicability of Ca 19-9 RIA in posttherapeutic case control for early registration of recurrences and metastases was examined. First analyses of our patient collective confirmed the assumption that increased serum concentrations of Ca 19-9 are detectable in gastrointestinal tumors as well as in mammary and bronchial carcinoma. Thus Ca 19-9 is a nonspecific tumor-associated antigen that by itself does not allow an organ correlation of malignancies of the gastrointestinal tract, breast, and lung.