Hepatocellular carcinoma and intrahepatic cholangiocarcinoma incidence between 2006 and 2015 in China: estimates based on data from 188 population-based cancer registries.

Background: Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) are the most common subtypes of primary liver cancer, but nationwide incidence of both liver cancer subtypes have never been reported in China. We aimed to estimate the most recent incidence of HCC and ICC and temporal trends in China based on the most updated data from high qualified population-based cancer registries (covering 13.1% of the national population), in comparison to those in the United States at the same period. Methods: We used data from 188 Chinese population-based cancer registries covering 180.6 million population of China to estimate the nationwide incidence of HCC and ICC in 2015. And 22 population-based cancer registries' data were used to estimate the trends of HCC and ICC incidence from 2006 to 2015. Multiple imputation by chained equations method was used to impute liver cancer cases with unknown subtype (50.8%). We used data from 18 population-based registries from the Surveillance, Epidemiology, and End Results program to analyze incidence of HCC and ICC in the United States. Results: In China, an estimated 301,500 and 61,900 newly diagnosed HCC and ICC occurred in 2015. The overall age-standardized rates (ASRs) of HCC incidence decreased by 3.9% per year. For ICC incidence, the overall ASR was relatively stable, but increased in the population of over 65 years old. Subgroup analysis by age showed that the ASR of HCC incidence had the sharpest decline in population who were less than 14 years old and received neonatally hepatitis B virus (HBV) vaccination. In the United States, though the incidence of HCC and ICC were lower than those in China, the overall HCC and ICC incidence increased by 3.3% and 9.2% per year. Conclusions: China still faces with a heavy burden of liver cancer incidence. Our results may further support the beneficial effect of Hepatitis B vaccination on reduction of HCC incidence. Both healthy lifestyle promotion and infection control are needed for future liver cancer control and prevention for China and the United States.