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

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.

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.

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.

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