Diagnosis of hepatocellular carcinoma by serial determination of serum alpha-fetoprotein concentration

This communication describes the clinical significance of serum α-fetoprotein (S-AFP) determined by radioimmunoassay (RIA) in the diagnosis of hepatocellular carcinoma (HCC). The sensitivity of the AFP assay with the α-Feto-125 kit produced by the Dainabot RI laboratories was over 2.5 ng/ml. Reproducibility of the kit was satisfactory; coefficient of variation was 6-10% within assays and 13% between assays. The mean and standard deviation of S-AFP in the sera of 30 healthy controls was 5.6+-2.6 ng/ml. When serum with a high level of S-AFP (2.9x105 ng/ml) was diluted with normal horse serum, the actual concentrations of AFP in the diluted serum were consistent with those determined. Thus, normal horse serum was employed to dilute the sera with high levels of AFP. Levels of S-AFP were over 2000 ng/ml in 75.5% of 49 cases with HCC, in 0.64% of 157 patients with hepatitis and cirrhosis of the liver, and in 3.8% of 52 cases of metastatic gastric cancer to the liver. In 20 patients with HCC, levels of S-AFP ranged widely from 7.5 to 9.5x105 ng/ml. In serial determinations of S-AFP in the clinical courses of patients such as those with S-AFP over 2000 ng/ml, the continuous increase of AFP was strongly suggestive of the presence of HCC. In 4 of 20 cases of HCC, the S-AFP levels remained under 300 ng/ml. Histological examination of these 4 cases of HCC showed Classes I and II, but no III in Edmondson's classification. Other cases of HCC with S-AFP levels over 300 ng/ml showed Edmondson's Classes II and III. (auth.)