Report of the 22nd nationwide follow-up Survey of Primary Liver Cancer in Japan (2012-2013).

In the 22nd Nationwide Follow-up Survey of Primary Liver Cancer in Japan, data from 21 155 newly registered patients and 43 041 previously registered follow-up patients were compiled from 538 institutions over a 2-year period from January 1, 2012 to December 31, 2013. Basic statistics compiled for patients newly registered in the 22nd survey were cause of death, past medical history, clinical diagnosis, imaging diagnosis, treatment-related factors, pathologic diagnosis, recurrence status and autopsy findings. Compared with the previous 21st survey, the population of patients with hepatocellular carcinoma (HCC) was older at the time of clinical diagnosis, had more female patients, more patients with non-B non-C HCC, smaller tumor diameter and was more frequently treated with hepatectomy. Cumulative survival rates were calculated for HCC, intrahepatic cholangiocarcinoma, and combined hepatocellular cholangiocarcinoma (combined HCC and intrahepatic cholangiocarcinoma) by treatment type and background characteristics for patients newly registered between 2002 and 2013 whose final outcome was survival or death. Median overall survival and cumulative survival rates for HCC were calculated by dividing patients by combinations of background factors (number of tumors, tumor diameter or Child-Pugh grade) and by treatment type (hepatectomy, radiofrequency ablation therapy, transcatheter arterial chemoembolization, hepatic arterial infusion chemotherapy and systemic therapy). The same values were also calculated according to registration date by dividing patients newly registered between 1978 and 2013 into five time period groups. The data obtained from this nationwide follow-up survey are expected to contribute to advancing clinical research and treatment of primary liver cancer worldwide.