Hepatitis B-related hepatocellular carcinoma: epidemiological characteristics and disease burden

Worldwide, 350 million people are chronically infected with hepatitis B virus (HBV) who are at greater risk of hepatocellular carcinoma (HCC) compared with uninfected people. The relative risks of HCC among people infected with HBV ranges from 5 to 49 in case-control studies and from 7 to 98 in cohort studies. More than 50% of HCC cases worldwide and 70-80% of HCC cases in highly HBV endemic regions are attributable to HBV. Incidence of HCC (per 100 000 person/year) among people with chronic HBV infection ranges from 400 to 800 in male and from 120 to 180 in female. Factors associated with increased risk of HCC include demographic characteristics (male sex and older age), lifestyles (heavy alcohol consumption and smoking), viral factors (genotype C, D F, high level of HBV DNA, core/precore mutation) and clinical factors (cirrhosis, elevated alpha-fetoprotein (AFP) and alanine aminotransferase (ALT)). HBV-related HCC has extremely poor prognosis with median survival less than 16 months. Survival rates of HBV-related HCC ranged from 36% to 67% after 1 year and from 15% to 26% after 5 year of diagnosis. Older age, liver function impairment, vascular invasion, tumour aggressiveness and elevated AFP are associated with HCC survival. Global burden of HBV-related liver disease is still a major challenge for public health in the 21st century. While decreases in incidence of HBV infection have been observed in birth cohorts following the introduction of universal infant HBV vaccination programme, HBV-related HCC incidence in is projected to increase for at least two decades because of the high prevalence of chronic HBV infection and prolonged latency to HCC development. To reduce HBV-related HCC continued expansion of universal infant HBV vaccination is required along with antiviral therapy targeted to those individuals at highest risk of HCC. Broad public health strategies should include routine testing to identify chronic HBV infection, improved health infrastructures including human resource to provide diagnosis and treatment assessment.