Usefulness of alpha-fetoprotein in the diagnosis of hepatocellular carcinoma

With the widespread use of ultrasonography (US) and computerized tomography (CT), the usefulness of a-fetoprotein assay in the diagnosis of hepatocellular carcinoma (HCC) has decreased. The aim of our study was to evaluate the best cut-off value for serum a-fetoprotein to discriminate between liver cirrhosis (LC) and HCC and the factors influencing levels in a Sicilian population. Three hundred and seventy-two patients with LC and 197 with HCC-associated LC were studied. The etiology, was: HCV in 288 cases (774%) of LC and 147 cases (75%) of HCC HBV in 31 cases (8.3%) of LC and 15 cases (7.6%) of HCC HCV/HBV in 21 cases (5.6%) of LC and 6 cases (3.0%) of HCC non-viral in 32 cases (8.6%) of LC and 29 cases (15%) of HCC. Hepatic function was estimated by the Child-Pugh's score; the TNM classification was used in HCC. The area under the ROC curve was 0.81+/-0.02, the best discriminant cut-off value, calculated as the value of the maximised likelihood ratio, was 30 ng/ml. At this level sensitivity (SE) was 65%, specificity (SP) 89%, positive predictive value (PPV) 74% and negative predictive value (NPV) 79%. When the patients were divided at this cut-off point into two groups according to viral or non-viral etiology, PPV was 70% versus 94%, respective (p < 0.05). In the non-viral diseases PPV reached 100% for AFP serum levels of 100 ng/ml, while in the viral diseases PPV was 100% when AFP was greater than 400 ng/ml. There were no significant differences in SE, SP or NPV between viral and non-viral liver diseases. Child's classes B and C were more frequent in HCC (chi(2) of MH 7.7, p < 0.0001). There was a correlation between AFP serum values and TNM classification (p < 0.02) and on multiple logistic regression AFP levels > 30 ng/ml correlated positively only with the TNM stage (p < 0.0001). In conclusion, the best cut-off value for serum AFP in our study population was 30 ng/ml, but at this level sensitivity was low. This cut-off value was more useful in detecting non-viral HCC, because PPV was significantly higher than in viral HCC therefore, our data confirm that the usefulness of AFP in the diagnosis of HCC of viral etiology is limited, being more useful in HCC of non-viral etiology.