[Comparison of the tumor markers CEA and CA 19-9 in colorectal diagnosis]

Endoscopic examination of the colon was performed in 405 patients (125 without, 217 with benign, and 63 with malignant colorectal diseases), and the serum levels of the tumour-associated antigens CEA and CA 19-9 were determined. On comparing both markers, the specificity of CA 19-9 (96% correctly normal values) was found to be higher in benign colorectal diseases than that of CEA (92% with a cut-off limit of 5 ng/ml for CEA). On the other hand, the sensitivity of CA 19-9 in colorectal carcinomas was only about 25% and thus much lower than that of CEA (52% correctly pathological values). The sensitivity of both markers was particularly low in the initial stages of carcinoma (in Dukes A: CEA 20%, CA 19-9 0%). If the cut-off limit for CEA was raised to 10 ng/ml, the specificity was increased to 99%, whereas the sensitivity was markedly reduced to 25%. The diagnostic accuracy of CEA in colorectal carcinomas was not surpassed by CA 19-9. There was no obvious advantage in simultaneous determination of CEA and CA 19-9.