Background & aims: Epidemiological studies have shown the relative roles of hepatitis B and C viruses in hepatocarcinogenesis to vary considerably among populations. The aim of this study was to define the independent and interactive roles of the two viruses in the genesis of hepatocellular carcinoma in southern African blacks.
Methods: Blood samples were taken from 231 black patients with hepatocellular carcinoma and matched controls treated at four Johannesburg hospitals. These were tested for hepatitis B surface antigen, antibodies to hepatitis C virus, and hepatitis C virus RNA.
Results: Relative to individuals without serological evidence of hepatitis B or C infection, those positive for hepatitis B surface antigen alone had a statistically significant 23.3-fold increased risk for hepatocellular carcinoma, whereas those positive for hepatitis C serology alone had a statistically significant risk of 6.6. A synergistic effect on risk was evident when both hepatitis B and C markers were present (relative risk, 82.5). Hepatitis B virus alone is estimated to cause 43% of hepatocellular carcinoma in southern African blacks, hepatitis C alone 5%, and coinfection with the two viruses 20%.
Conclusions: Hepatitis B virus plays a predominant role in hepatocellular carcinogenesis in southern African blacks, with hepatitis C virus responsible for a smaller proportion of cases. Coinfection with the two viruses carries a synergistic risk of hepatocellular carcinoma formation.