Examining Differences in Liver Cancer Incidence Across 7 Countries

Comparing liver cancer survival across high-income countries has been difficult due to different standard and coding practices

Liver cancer rates rose in 7 high-income European countries after 1995, according to a new study.

Over the time period of the study, survival was found to be poor in all countries, and the incidence of hepatocellular carcinoma (HCC) rose as detection methods shifted to less invasive techniques.

Comparing liver cancer survival across high-income countries has been difficult due to different standard and coding practices. In addition, there are challenges due to defining primary and secondary tumors, the authors noted.

A recent study sought to compare liver cancer survival across countries participating in the International Cancer Benchmarking Partnership (ICBP), which was created to study international variation in cancer survival, and to inform policy to improve survival.

Investigators wanted to look at the comparability of estimates through a range of sensitivity analyses, using liver cancer incidence data from 21 jurisdictions in 7 countries: Australia, Canada, Denmark, Ireland, New Zealand, Norway, and the United Kingdom.

Researchers used population-based registries for 1995-2014 and categorized cases based on histological classification, age groups, basis of diagnosis and calendar period. They also estimated the age-standardized incidence rate (ASR) per 100,000 and net survival at 1 and 3 years after diagnosis.

The largest relative increase was seen in the United Kingdom, as HCC rose from 1.3 to 4.4 per 100,000 person-years between 1995 and 2014.

Australia had the highest age-standardized 1-year and 3-year net survival for all liver cancers (HCC and intrahepatic cholangiocarcinomas) combined (48.7% and 28.1%, respectively) but survival was higher for HCC alone, compared with intrahepatic cholangiocarcinoma.

Cases that were morphologically verified had the highest survival, but since the proportion of nonmicroscopically verified cases is rising, survival estimates for all liver tumors combined should be viewed within that context, the authors said.

In addition, international comparisons should involve comparable patients, and researchers should keep in mind coding practice variations, they noted.

“Common adoption and regular updates of international guidelines for cancer registries to create harmonised coding and classification decisions would improve the comparability of international survival comparisons for liver cancer,” the authors concluded.

Reference

Rutherford MJ, Arnold M, Bardot A, et al. Comparison of liver cancer incidence and survival by subtypes across seven high-income countries. Health Policy. Published online August 30, 2021. doi: 10.1016/j.healthpol.2013.03.021