Introduction: Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA) are the two main histological subtypes of primary liver cancer. Estimates of the burden of liver cancer by subtype are needed to facilitate development and evaluation of liver cancer control globally. We provide worldwide, regional and national estimates of HCC and iCCA incidence using high-quality data. Methods: We used population-based cancer registry data on liver cancer cases by histological subtype from 95 countries to compute the sex- and country-specific distributions of HCC, iCCA and other specified histology. Subtype distributions were applied to estimates of total liver cancer cases for 2018 from the Global Cancer Observatory. Age-standardised incidence rates (ASRs) were calculated. Results: There were an estimated 826,000 cases of liver cancer globally in 2018: 661,000 HCC (ASR 7.3 cases per 100,000); 123,000 iCCA (ASR 1.4) and 42,000 other specified histology (ASR 0.5). HCC contributed 80% of the world total liver cancer burden followed by iCCA (14.9%) and other specified histology (5.1%). HCC rates were highest in Eastern Asia (ASR 14.8), Northern Africa (ASR 13.2) and South-Eastern Asia (ASR 9.5). Rates of iCCA were highest in South-Eastern Asia (ASR 2.9), Eastern Asia (ASR 2.0), Northern Europe, the Caribbean and Central America and Oceania (ASR all 1.8). Conclusion: We have shown the importance of uncovering the distinct patterns of the major subtypes of liver cancer. The use of these estimates is critical to further develop public health policy to reduce the burden of liver cancer and monitor progress in controlling HCC and iCCA globally.
Bibliographical noteFunding Information:
The authors would like to thank all population-based cancer registries and their staff who have contributed by sharing the data needed for this study. The work reported by HR in this article was undertaken during a PhD studentship at the International Agency for Research on Cancer. Where authors are identified as personnel of the International Agency for Research on Cancer/World Health Organization, the authors alone are responsible for the views expressed in this article, and they do not necessarily represent the decisions, policy or views of the International Agency for Research on Cancer/World Health Organization.