Epidemiology of non-alcoholic fatty liver disease-related hepatocellular carcinoma and its implications

Hepatocellular carcinoma (HCC) is the fifth most common cancer and the second leading cause of cancer-related mortality worldwide. Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of liver pathology that is characterized by the excessive accumulation of fat in the liver attributable to overnutrition and is strongly associated with the metabolic syndrome. Non-alcoholic steatohepatitis is the more severe form of NAFLD that is defined histologically by the presence of lobular inflammation and hepatocyte ballooning. Non-alcoholic steatohepatitis patients have a greater tendency to develop advanced liver fibrosis, cirrhosis, and HCC. This review focuses on the epidemiology of NAFLD-related HCC and its implications. NAFLD has been estimated to contribute to 10-12% of HCC cases in Western populations and 1-6% of HCC cases in Asian populations. NAFLD-related HCC is expected to increase in Asian populations, in line with the increased prevalence of NALFD similar to that of Western populations in recent years. The increasing burden of NAFLD-related HCC over time has been demonstrated in studies from both Western and Asian populations. Certain factors such as ethnicity, obesity, and diabetes mellitus appear to have an incremental effect on the risk of developing HCC among NAFLD patients. The difficulty in identifying NAFLD patients with cirrhosis and the possibility of HCC developing in noncirrhotic NAFLD patients are challenges that need to be addressed. Further understanding of these gaps may contribute to better surveillance strategies for the early detection of HCC in NAFLD patients to reduce the mortality and improve the survival of these patients.