Review of Hepatocellular Carcinoma: Epidemiology, Etiology, and Carcinogenesis

Since the 1970s, the epidemic of hepatocellular carcinoma (HCC) has spread beyond the Eastern Asian predominance and has been increasing in Northern hemisphere, especially in the United States (US) and Western Europe. It occurs more commonly in males in the fourth and fifth decades of life. Among all cancers, HCC is one of the fastest growing causes of death in the US and poses a significant economic burden on healthcare. Chronic liver disease due to hepatitis B virus or hepatitis C virus and alcohol accounts for the majority of HCC cases. Incidence of nonalcoholic fatty liver disease has been on the risem and it has also been associated with the development of HCC. Its pathogenesis varies based on the underlying etiological factor although majority of cases develop in the setting of background cirrhosis. Carcinogenesis of HCC includes angiogenesis, chronic inflammation, and tumor macroenvironment and microenvironment. There is a significant role of both intrinsic genetic risk factors and extrinsic influences such as alcohol or viral infections that lead to the development of HCC. Understanding its etiopathogenesis helps select appropriate diagnostic tests and treatments.