The evolving epidemiology of hepatocellular carcinoma: a global perspective

Abstract

Primary liver cancer, the majority of which are hepatocellular carcinomas, is now the second leading cause of cancer death worldwide. Hepatocellular carcinoma is a unique cancer that typically arises in the setting of chronic liver disease at a rate dependent upon the complex interplay between the host, disease and environmental factors. Infection with chronic hepatitis B or C virus is currently the dominant risk factor worldwide. However, changing lifestyle and environmental factors in western countries plus rising neonatal hepatitis B vaccination rates and decreasing exposure to dietary aflatoxins in developing countries are driving an evolution of the epidemiology of this cancer. An understanding of this change is crucial in combating the rising incidence currently being seen in western regions and will underpin the efforts to reduce the mortality rates associated with this cancer.

Keywords:

• chronic viral hepatitis
• cirrhosis
• epidemiology
• hepatocellular carcinoma
• nonalcoholic fatty liver disease

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Primary liver cancer is now the fifth most common frequently occurring cancer in men, the ninth in women and is the second leading cause of death from cancer worldwide.

• Hepatocellular carcinoma (HCC) contributes up to 40% of all deaths in cirrhosis, making it the single most common cause of death in this patient population.

• There is a clear geographical distribution in the epidemiology of hepatocellular carcinoma, with the highest incidence seen in developing countries with high rates of chronic hepatitis B and aflatoxin exposure and the lowest in some European countries.

• HCC development depends upon a multitude of factors, including etiology and severity of underlying liver disease, host, lifestyle, behavioral and environmental risk factors.

• A shift in the risk factor profile is driving a clear evolution in the epidemiology of hepatocellular carcinoma; in general, rates are decreasing in high incidence areas and are increasing in low incidence areas.

• Most cases arise in China (50% of cases) and in the setting of chronic hepatitis B or C.

• Increasing hepatitis B vaccination and treatment, reducing levels of aflatoxin exposure and more efficacious hepatitis C treatment are likely to change the global epidemiology of HCC in the near future.

• Metabolic disorders, including fatty liver disease, obesity and insulin resistance are emerging risk factors for hepatocellular carcinoma, and these may become dominant risk factors in western regions in the coming decade.

• The future burden of HCC, particularly in western populations, is also likely to be dependent upon whether the epidemic of obesity, diabetes mellitus and fatty liver can be stemmed.

Notes