Hepatocellular carcinoma: recent trends in Japan

During the past 20 years, primary liver cancer, 95% of which is hepatocellular carcinoma (HCC), has ranked third in men and fifth in women as a cause of death from malignant neoplasm in Japan. The numbers of deaths and death rate from HCC showed a sharp increase beginning in 1975. Although both hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are important causes, HCV-related HCC has accounted for most of the recent increase and now represents 75% of all HCC in Japan. Geographically, HCC is more frequent in western than eastern Japan, and the death rate of HCC in each prefecture correlates with prevalence of anti-HCV. Among patients with HCV-related HCC, a history of blood transfusion was a relatively important source of infection in the 1990s, whereas community-acquired infections increased after 2000. There was a negative correlation between the duration from onset of infection to development of HCC and the age at onset. Interferon therapy for chronic hepatitis C has reduced the risk for HCC, indicating that early detection of HCV carriers and better treatment will contribute to improved outcomes. Nationwide screening for HCV and HBV began in 2002 in Japan, and reduction of HCC is anticipated. Further research should focus on mechanisms of carcinogenesis by HCV and HBV, development of more effective treatments, and establishment of early detection and treatment approaches. Better understanding of HCC unrelated to HCV and HBV and possibly because of steatohepatitis and diabetes should also be a major concern in future studies.