Determination and significance of a new carbohydrate antigen CA19-9 in digestive system cancers.

To assess the diagnostic significance of CA19-9, the serum levels in 225 healthy subjects, 201 patients with cancers, 423 patients with benign diseases and 21 pregnant women, were determined by RIA. The mean CA19-9 level of the healthy subjects was 11.2 +/- 0.4 U/ml (range, 6-100 U/ml). Only 3.1% of them were above 37 U/ml. The CA19-9 levels were elevated above 37 U/ml in 7.9% of 293 patients with non-carcinomatous diseases of the digestive system. Among digestive system cancers, elevated levels were found in 18.2% of 11 patients with esophageal cancer, 42.7% of 68 patients with gastric cancer, 39.1% of 23 patients with colorectal cancer, 27.8% of 18 patients with primary hepatic cancer, 71.4% of 35 patients with biliary cancer, and 75% of 20 patients with pancreatic cancer. Most of the patients with levels above 100 U/ml had carcinomatous diseases. The CA19-9 positive rates for patients with gastric cancer and colorectal cancer were extremely low at stages I, II and III, while in patients at stage IV and in patients with recurrent cancer, a tendency for rapid increase in the positive rates and concentrations of CA19-9 was noted. Based on combination assay of CA19-9, CEA and ferritin, in comparison with the positive rates for CA19-9 alone, it was found that the rates were raised to 42.7% in gastric cancer, to 39.1% in colorectal cancer, and to 71.4% in biliary cancer, suggesting the simultaneous determination with these tumor markers may serve to elevate their usefulness.