Report of the 19th follow-up survey of primary liver cancer in Japan.

The 19th Nationwide Follow-up Survey of Primary Liver Cancer in Japan comprised 20 850 primary liver cancer patients newly registered at 482 medical institutions over a period of 2 years (from 1 January 2006 to 31 December 2007). Of these, 94.7% had hepatocellular carcinoma (HCC) and 4.4% had intrahepatic cholangiocarcinoma (ICC). In addition, follow-up data were obtained regarding 34 752 patients who were registered in the previous survey. Epidemiological and clinicopathological factors, diagnosis, and treatment were examined in newly registered patients. Compared with the 18th follow-up survey, the present follow-up survey suggested an increase in the number of elderly and female patients, a reduction in the number of hepatitis B surface antigen- and anti-hepatitis C virus antibody-positive patients, and a reduction in tumor size at the time of clinical diagnosis. In terms of local ablation therapy, the number of patients receiving radiofrequency ablation therapy increased. The cumulative survival rates for newly registered patients between 1996 and 2007 were calculated for each histological type (HCC, ICC, and combined HCC and ICC) and stratified according to background factors and treatments. The cumulative survival rates of newly registered patients between 1978 and 2007 were calculated after dividing individuals into groups according to registration date (1978-1987, 1988-1997, and 1998-2007). The data obtained from this follow-up survey will contribute to the medical management of primary liver cancer and facilitate future research.