Liver cancer in Japan: epidemiological transition, viral hepatitis control, and emerging challenges

Japan has seen a dramatic shift in liver cancer epidemiology, with hepatocellular carcinoma (HCC) declining after decades of comprehensive viral hepatitis control, illustrating the impact of sustained public health intervention. This review examines trends in liver cancer epidemiology in Japan in the context of long-term viral hepatitis control. National data indicate a substantial reduction in disease burden, with liver cancer mortality declining from 34,637 deaths in 2002 to fewer than 30,000 in 2014. The incidence of newly acquired infections is low, with HCV estimated at approximately 0.4 per 100,000 person-years and HBV at 2.38 per 100,000 person-years. These trends likely reflect population-based screening, universal health coverage, and expanded access to antiviral therapy. However, the aetiology of HCC is evolving, with non-viral causes increasing from 6.8% in 1991 to 41.1% in 2015 and accounting for 56.0% of HCC deaths in 2019. Overall, Japan's experience suggests progress in viral hepatitis control, while highlighting the need to address metabolic and lifestyle-related risk factors to sustain future prevention of liver cancer.