Epidemiology and Risk Factors of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer. Cirrhosis is present in the majority of people who decelop HCC. The main risk factors for HCC are chronic viral hepatitis (hepatitis B and C), alcoholic and non alcoholic fatty liver disease. There are remarkable geographical, racial, as well as sex-related variations in the incidence and mortality of HCC. Some of these variations are explained by the prevalence and duration of the main risk factors. Additional risk factors include diabetes, obesity, aflatoxin, and tobacco smoking. In general, the incidence of HCC has been decreasing in areas endemic for hepatitis B and increasing or plateuing in areas with predominance of hepatitis C and non alcoholic cirrhosis. Within each major risk factors, there are multiple clinical, genetic and life style factors that further determine the magnitude of HCC risk within these groups. There has been a shift in the main HCC risk factors from strong but relatively infrequent agents (e.g., hepatitis B and C) to weak but very common conditions (e.g., obesity, diabetes, metabolic syndrome). There is a decline in the incidence of HBV and HCV (i.e., vaccination, screening of blood products), prevalence of HCV (i.e., effective novel HCC therapies), and carcinogenic potential of HCV (i.e., treatment related sustained virological response) and HBV (i.e., treatment related adequate viral suppression).