Relationship between tissue and serum concentrations of carcinoembryonic antigen (CEA) in gastric and colonic...

A relationship between tissue and serum concentrations of carcinoembryonic antigen (CEA) as determined by monoclonal enzymo-immunoassay (EIA) was studied in 47 patients with gastric carcinoma and 46 patients with colorectal carcinoma. The values were then compared to those obtained in a control group of 64 healthy subjects. On the basis of results, an increase in tissue CEA is not paralleled by a simultaneous increase in serum CEA. Serum CEA depends on tumor mass and points to the process extension. There is no specific tissue CEA threshold above which the serum CEA concentration should unavoidably increase. A relationship between tissue and serum CEA concentrations according to the degree of differentiation, studied in colorectal carcinomas, revealed significantly lower values of tissue CEA concentration in poorly differentiated carcinomas, whereas serum CEA concentrations did not show any such difference. The present study has suggested that, having identified both tissue and serum CEA concentrations in colorectal carcinoma, the tumor, its size and differentiation could be readily and quite closely defined at the time of measurements.