Incidence Trends of Primary Liver Cancer in Different Geographical Regions of China from 1978 to 2012 and Projections to 2032: An Age-period-cohort Analysis

China accounted for 45.3% of new cases of primary liver cancer (PLC) worldwide in 2020. While variations in PLC incidence between different regions of China and decreasing incidence in overall China have been reported, incidence patterns have not been thoroughly explored by region. We examined the nearly status and temporal trends of PLC incidence in different geographical regions in China and project future trends. The age-standardized incidence rate (ASR) was estimated for 1978 to 2012 by different geographical regions and gender in China. Age-period-cohort model was adopted to evaluate age and birth cohort effects on the temporal trend of five registries of China (Hong Kong, Shanghai, Jiashan, Harbin and Zhongshan), Bayesian age-period-cohort model was adopted to project future trends for 2013 to 2032. PLC incidence in China exhibits marked geographical disparity, with the highest incidence in Southwest China, and gender differences being particularly pronounced in South China. While other registries exhibited decreasing trend, Zhongshan exhibited an increasing trend, with the cohort effect showing a marked upward trend for females born in 1916 to 1949 and males born in 1916 to 1962. During 2013 to 2032, the ASR appears to increase by 86.9% for men and 40.0% for women in Zhongshan, while the remaining registries will decline by around 50%. Since the high incidence of hepatitis B virus infection in early birth cohort, recent rise of nonviral risk factors and the severe aging of the Chinese population, it may be critical to tailor future prevention and control strategies for PLC to the distribution of risk factors in different geographical regions.