A two antibody system for radioimmunoassay of carcinoembryonic antigen (CEA) was established and the specificity was verified with respect to the non-specific cross-reacting antigens (NCA & NCA-2) of von Kleist and Burtin.
The diagnostic significance of serum CEA determination was evaluated on various diseases, especially on cancer of digestive organs.
As the results, increases of serum CEA levels were seen in 64% of patients with colo-rectal cancer and in 47 to 69% of patients with cancers of the pancreas, liver and the lung, compared with the normal upper range of 10u/ml in healthy control sera. Slight elevations of serum CEA concentration were also seen in a few patients with atrophic gastritis and with liver diseases.
On the relation between serum CEA levels and disease states of gastric carcinoma according to the stage classification by the General Rules for the Gastric Cancer Study (Japanese Research Society for Gastric Cancer), significant increases were found in cases of stage III and IV as compared with those of stage I and II, and a remarkable rise was noted in sera of patients with liver metastasis.
On the clinical follow-up studies, marked decreases of serum CEA levels were seen both in patient group showing good response to chemotherapy and in group subjected to curative surgery, while clear increase of serum CEA levels was found in the majority of patients with progression of the disease states.
From the results, it is said that serum CEA level shows a good correlation with the clinical course in some patients with carcinoma of the digestive organs.
Although the determination of serum CEA is not an useful method for the diagnosis of these cancers on their early stages, it should be said to be helpful for a diagnostic aid to detect the liver metastasis and to evaluate the prognosis or clinical condition during the treatment.
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