| Hepatocellular carcinoma (HCC) is the fifth most common cancer and the second leading cause of cancer deaths worldwide. The risk factors associated with the development of HCC include chronic infection with either HBV or hepatitis C virus (HCV), the presence of cirrhosis, carcinogen exposure especially aflatoxin B1 (AFB1), alcohol abuse, genetic factors, male gender, cigarette smoking, and advanced age. Overall, at least 75-80% of HCC are attributable to persistent viral infections with either HBV (50-55%) or HCV (25-30%). Due to differences in the prevalence of viral hepatitis, the incidence of HCC in low and middle income countries is much higher than that of high income countries. In HBV endemic regions like Taiwan, chronic HBV infection has the strongest association with the development of HCC. Strategies to limit the impact of HBV-related HCC include primary prevention against new cases of HBV infection by the implementation of universal hepatitis B vaccination, secondary prevention of HCC occurrence by treating chronic hepatitis B (CHB) patients at risk of disease progression and early HCC detection by surveillance program, and tertiary prevention of HCC recurrence after curative therapy by antiviral treatment. For example, serial studies from Taiwan showed that universal hepatitis B vaccination has resulted in dramatic reduction in incident cases of CHB and HCC in children, adolescents and young adults. The major barrier for universal vaccination is the cost and the accessibility in resources constrained countries. In addition, randomized controlled trials and meta-analyses showed that successful treatment of chronic hepatitis B can reduce the risk of HBV-related HCC and cirrhotic complications. Surveillance in at-risk CHB patients by periodic ultrasonography examination and alpha fetoprotein testing leads to early HCC detection and high likelihood of curative therapy. A population-based cohort study from Taiwan showed that nucleoside analogue use is associated with a lower risk of HCC recurrence in HBV-related HCC patients after curative surgery. In summary, it is now possible to prevent HCC in HBV infection. The successful story in Taiwan confirm that the most cost-effective way is the universal hepatitis B vaccination, which prevents chronic HBV infection and chronic liver disease. Although antiviral treatment has been shown to reduce HCC occurrence and recurrence in CHB patients and HCC patients who receive curative therapy, respectively, the risk of HCC still exists. More studies are urgently needed to identify predictors of HCC development and novel agents to further reduce HCC in these patients. |
