Effect of hepatitis C and B virus infection on risk of hepatocellular carcinoma: a prospective study.

To assess whether there is an additive effect between chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infection on the development of hepatocellular carcinoma (HCC), 400 consecutive cirrhotic patients were followed prospectively with periodic abdominal ultrasound examination and measurement of serum alpha-fetoprotein (AFP) level every 4 months. During a follow-up of 1185 person-years, 80 (20%) patients developed HCC, with an annual incidence of 6.8%. The annual incidence was 2.0% in patients negative for hepatitis B surface antigen (HBsAg) and antibodies to HCV (anti-HCV), 6.6% in patients with HBsAg alone, 7.0% in patients with anti-HCV alone and 13.3% in patients co-infected with HBV and HCV. There was a positive linear trend in the annual incidence of HCC among patients without either marker, patients with single viral infection and patients with dual viral infection (P[for trend] < 0.0001). Cox's proportional hazard model indicated that HCV/HBV co-infection [hazard ratio (HR), 6.41; 95% confidence interval (CI), 1.80-22.80], anti-HCV alone (HR, 3.74; 95% CI, 1.07-13.07) and HBsAg alone (HR, 4.06; 95% CI, 1.23-13.34) were independently risk factors of HCC. In conclusion, there is an additive and independent effect modification of HCV and HBV infection on HCC development.