Report of the 21st Nationwide Follow‐up Survey of Primary Liver Cancer in Japan (2010–2011)

In the 21st Nationwide Follow‐up Survey of Primary Liver Cancer in Japan, data from 22,134 new patients and 41,956 previously followed patients were compiled from 546 institutions over a 2‐year period from 1 January 2010 to 31 December 2011. Basic statistics compiled for patients newly registered in the 21st survey were cause of death, medical history, clinical diagnosis, imaging diagnosis, treatment‐related factors, pathological diagnosis, recurrence status, and autopsy findings. Compared with the previous 20th survey, the population of patients with hepatocellular carcinoma (HCC) was older at the time of clinical diagnosis, had more female patients, had more patients with non‐B non‐C HCC, had smaller tumor diameter, and was more frequently treated with hepatectomy and with radiofrequency ablation. 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 1998 and 2011 whose final outcome was survival or death (excluding unknown). Cumulative survival rates for HCC were calculated by dividing patients by combinations of background factors (number of tumors, tumor diameter, and Child–Pugh grade) and by treatment type (hepatectomy, local ablation therapy, transcatheter arterial chemoembolization, and hepatic arterial infusion chemotherapy). The same values were also calculated according to registration date by dividing patients newly registered between 1978 and 2011 into four 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.