Noninvasive diagnostic criteria for hepatocellular carcinoma in hepatic masses > 2 cm in a hepatitis B virus-endemic area

Background: Noninvasive criteria for diagnosing hepatocellular carcinoma (HCC) suggested by the American Association for the Study of Liver Diseases (AASLD) in 2005 consisted of serum alpha-fetoprotein (AFP) level > 200 ng/ml or a typical enhancement pattern (arterial enhancement and portal/delayed washed out) on dynamic imaging of hepatic mass(es) > 2 cm in a cirrhotic liver. Aims: To validate these criteria in a Korean population and to evaluate whether these criteria are applicable to patients without cirrhosis at a high risk of developing HCC. Methods: We prospectively investigated 206 consecutive patients with hepatic mass(es) > 2 cm who underwent biopsy or surgical resection. Patients were evaluated by four-phase dynamic computed tomography (CT) and by assays of serum AFP concentrations at baseline. Patients were classified according to the presence of risk factors or cirrhosis, and the diagnostic accuracy of each test was determined. Results: The positive predictive values (PPV) of typical CT findings or serum AFP > 200 ng/ml were 97.8% in cirrhotic patients, 89.6% in high-risk patients without cirrhosis and 82.4% in low-risk patients. The PPVs of typical CT findings alone in these groups were 98.8, 97.6 and 87.5% respectively. In high-risk patients without cirrhosis, the addition of serum AFP levels to typical CT findings minimally increased the diagnostic sensitivity from 81.6 to 87.8% but reduced the PPV from 97.6 to 89.6%. Conclusions: Serum AFP concentration is not a suitable diagnostic criterion for HCC. Typical CT findings can be used to diagnose HCC > 2 cm both in cirrhotic patients and in high-risk patients without cirrhosis.