CEA Carcinoma Monitoring by Two RIA

A comparison was made of the accuracy of two CEA assays by RIA in diagnosis of different cancers. The basis of the study was a consecutive series of 76 patients thought to have bladder, colon, stomach or pancreas pathology, or a space occupying lesion; cancer was the final diagnosis in 46. The RIA assay method of Hoffman-La Roche and the CIS (Sorin) direct double antibody RIA assay were used for CEA detection. Results were correlated with the clinical and follow up evaluation. Samples were taken before operation, immediately after, and 1,2, 3 and 6 months after. Ninety eight per cent of the patients with a negative diagnosis for cancer had no detectable CEA, or levels below 2.5 ng/ml with Roche assay, and below 8 ng/ml with CIS assay. Abnormal CEA levels were found in the different groups as follows: with the Roche assay bladder—22%, colon—45%, stomach—23%, and pancreas—40%, with the CIS assay bladder—66%, colon—61%, stomach—38% and pancreas—60%. We conclude that neither test is ideal for clinical purposes although the CIS assay is probably more sensitive than the Roche assay. Both assays are useful in the monitoring and detection of recurrent tumors.