Serum des-gamma-carboxyprothrombin concentration determined by the avidin-biotin complex method in small hepatocellular carcinomas.

BACKGROUND: Des-gamma-carboxyprothrombin (DCP) is a useful tumor marker for hepatocellular carcinoma (HCC). The present method for measurement of DCP concentration, however, does not have adequate sensitivity to detect small HCCs.

METHODS: The serum DCP concentration was investigated by the avidin-biotin complex (ABC) method in patients with an HCC smaller than 20 mm in maximum dimension. A serum DCP concentration greater than 4.0 arbitrary units per liter using the ABC method was considered abnormal.

RESULTS: Of 115 patients with small HCC, 45 (39.1%) had an abnormal DCP concentration. Ten of 141 patients with chronic hepatitis (7.1%), 18 of 115 (15.7%) with cirrhosis, and 0 of 30 normal control patients had abnormal DCP concentrations. This method yielded a sensitivity of 39.1%, a specificity of 89.1%, a positive predictive value of 61.6%, and a negative predictive value of 76.5% for detection of small HCC. The detectability of HCC increased to 56.5% when alpha-fetoprotein (AFP) was was measured (> 40 ng/ml). Abnormal DCP concentrations were seen in 8 of 34 (23.5%), 24 of 42 (57.1%), and 5 of 7 (71.4%) patients with Edmondson's Grade I, II, and III tumors, respectively. There was a significant relationship between DCP concentrations and histologic grade (P = 0.0017), but there was no association between DCP concentration and other patient characteristics. Elevation of serum AFP concentrations in patients with hepatitis B surface antigen positivity, however, was more frequent than that in patients who were antihepatitis C virus (HCV) positive. Therefore, the measurement of serum DCP concentrations may be more useful than that of serum AFP concentrations in patients with anti-HCV positivity.

CONCLUSIONS: The measurement of serum DCP concentrations by the ABC method is a useful diagnostic tool for the monitoring of small HCC.