THE RELATIVE ROLES OF HEPATITIS-B AND HEPATITIS-C VIRUSES IN THE ETIOLOGY OF HEPATOCELLULAR-CARCINOMA IN SOUTHERN AFRICAN BLACKS

Background & Aims: Epidemiological studies have shown the relative rol es of hepatitis B and C viruses in hepatocarcinogenesis to vary consid erably among populations, The aim of this study was to define the inde pendent and interactive roles of the two viruses in the genesis of hep atocellular carcinoma in southern African blacks, Methods: Blood sampl es were taken from 231 black patients with hepatocellular carcinoma an d matched controls treated at four Johannesburg hospitals, These were tested for hepatitis B surface antigen, antibodies to hepatitis C viru s, and hepatitis C virus RNA, Results: Relative to individuals without serological evidence of hepatitis B or C infection, those positive fo r hepatitis B surface antigen alone had a statistically significant 23 .3-fold increased risk for hepatocellular carcinoma, whereas those pos itive for hepatitis C serology alone had a statistically significant r isk of 6.6, A synergistic effect on risk was evident when both hepatit is B and C markers were present (relative risk, 82.5), Hepatitis B vir us alone is estimated to cause 43% of hepatocellular carcinomas in sou thern African blacks, hepatitis C atone 5%, and coinfection with the t wo viruses 20%, Conclusions: Hepatitis B Virus plays a predominant rol e in hepatocellular carcinogenesis in southern African blacks, with he patitis C virus responsible for a smaller proportion of cases, Coinfec tion with the two viruses carries a synergistic risk of hepatocellular carcinoma formation.