Report of the 18th follow-up survey of primary liver cancer in Japan

In the 18th Nationwide Follow-Up Survey of Primary Liver Cancer in Japan, 20 753 people were newly registered as patients with primary liver cancer at 544 medical institutions over a period of 2 years (from 1 January 2004 to 31 December 2005). Of these patients, 94.0% had hepatocellular carcinoma (HCC) and 4.4% had intrahepatic cholangiocarcinoma (ICC). In addition, 30 677 follow-up patients were registered in the survey. Epidemiological and clinicopathological factors, diagnosis and treatment were investigated in the newly registered patients. Compared with the 17th follow-up survey, this follow-up survey in HCC indicated an increase in elder patients and women, a decrease in patients positive for hepatitis B surface antigen and hepatitis C virus antibody, and a decrease in tumor size at the clinical diagnosis. In the local ablation therapy, ratio of radio frequency ablation therapy was increasing. The cumulative survival rates of newly-registered patients between 1994 and 2005 were calculated for each histological type (HCC, ICC, and combined HCC and ICC) and stratified by background factors and treatment. The cumulative survival rates of newly-registered patients between 1978 and 2005 divided into three groups (1978-1985, 1986-1995 and 1996-2005) were also calculated. The data obtained in this follow-up survey should contribute to future research and medical practice for primary liver cancer.