Comparison of CA-50, a new tumour marker, with carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) in patients with gastrointestinal diseases

Serum levels were determined in 434 patients with benign and malignant gastrointestinal diseases and compared with the serum concentrations of carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP). The highest proportion of elevated CA-50 levels (greater than 17 U ml-1) was found in patients with pancreatic cancer (73%). High levels were mainly associated with advanced cancer, but also half of the patients with a resectable pancreatic tumour had an increased CA-50 concentration. The CA-50 level was elevated in 37-58% of patients with colorectal, gastric, hepatocellular and biliary tract cancers. In all gastrointestinal cancers, CA-50 gave additional information compared with CEA and AFP, except in hepatocellular carcinoma where AFP was the best marker.