HEPATOMA-SPECIFIC ALPHA-FETOPROTEIN MAY PERMIT PRECLINICAL DIAGNOSIS OF MALIGNANT CHANGE IN PATIENTS WITH CHRONIC LIVER-DISEASE

The only hope for effective treatment of hepatocellular carcinoma (HCC or 'hepatoma') lies in early diagnosis. Measurement of the serum alph afetoprotein (AFP) level is potentially a useful screening test. When grossly raised, it is almost diagnostic of HCG. However, modestly elev ated levels may also arise in patients with benign chronic liver disea se, and this markedly decreases the test's specificity and hence its c linical value. in 582 consecutive attendees at an outpatient clinic fo r people with chronic liver disease, a single blood sample was taken f or analysis of 'total' AFP and the 'hepatoma-specific' AFP isoform. Us ing ultrasonography as the primary screening method, patients with AFP levels greater than or equal to 50 ng ml(-1) were followed up through out the study or until HCC was diagnosed on the basis of conventionall y defined criteria. On entry into the study, 53 patients had an AFP co ncentration greater than or equal to 50 ng ml(-1) and the 'hepatoma-sp ecific' AFP isoform was detected in 26 of these. During an 18-month fo llow-up period, a diagnosis of HCC was established by conventional met hods in 19 (17 'definite' and two 'probable') of these 26 patients. In only two cases was there ultrasound evidence of tumour development at the time AFP was first found to be elevated; in the remainder a diagn osis of HCC, based on ultrasound screening, was established at a media n time of 3.6 months (range 1-18 months) after entry into the study. A mong those 27 without the 'hepatoma-specific' isoform, one developed a 'definite' HCC and two developed 'probable' tumours. With the applica tion of 'hepatoma-specific' AFP, the positive predictive Value of the test was 73.1%, compared with only 41.5% using the conventional 'total ' AFP test. Application of this test for the 'hepatoma-specific' AFP m arkedly increases the positive predictive value of AFP and, in some ca ses, permits the presence of tumour to be inferred before it could be detected by routine ultrasound examination.