New Cancer Study Estimates the Global Burden of Infection-Attributable Cancers

A series of enhanced understanding of the links between infections and cancer in the past 60 years has been accompanied by increasing prospects for cancer prevention, reported a new study published in The Lancet.

The good news from this study published on December 17, 2019, is many carcinogenic infections are potentially modifiable risk factors, for which prevention tools already exist. 

These researchers said ‘of the 11 infectious pathogens classified as group 1 carcinogens by the International Agency for Research on Cancer (IARC), we have previously shown that the 4 most important are Helicobacter pylori, high-risk human papillomavirus (HPV), hepatitis B virus (HBV), and hepatitis C virus (HCV).’

Periodical assessments by IARC have focused on the global and regional proportions and numbers of cancers due to oncogenic infections. 

Together, they account for more than 90 percent of infection-related cancers worldwide. 

These findings have translated into bold proposals for high-level action from the scientific and public health community.

• In 2014, IARC published a working group report on strategic eradication of H pylori to prevent gastric cancer.
• In May 2016, the World Health Assembly endorsed the Global Health Sector Strategy for 2016–21 that proposes to eliminate viral hepatitis as a public health threat by 2030.
• In May 2018, the Director-General of the World Health Organization (WHO) announced a global call for action towards the elimination of cervical cancer through the scale-up of effective vaccination, screening, and treatment.

Building upon the methods developed in these assessments, improving estimates by using relevant histological subtypes derived from cancer registries and using newly released data for 2018 from GLOBOCAN—the online IARC database providing estimates of incidence and mortality rates in 185 countries for 36 types of cancer—we aimed to estimate the incidence of infection-attributable cancers at the country level for 2018. 

This approach provides an absolute measure of the burden of infection-related cancers, irrespective of population size. 

We then aggregated these estimates into geographical regions and World Bank income groups to obtain an overview of the burden of infection-attributable cancers at a subregional, regional, and global level.

These researchers found that, for 2018, an estimated 2.2 million infection-attributable cancer cases were diagnosed worldwide, corresponding to an infection-attributable ASIR of 25 cases per 100,000 person-years.

Primary causes were Helicobacter pylori (810,000 cases), HPV (690,000), hepatitis B virus (360,000) and hepatitis C virus (160 000).

Infection-attributable ASIR was highest in eastern Asia (37.9 cases per 100,000 person-years) and lowest in northern Europe (13.6).

The cancer burden attributed to HPV showed the clearest relationship with country income level (from ASIR of 6.9 cases per 100,000 person-years in high-income countries to 16.1 in low-income countries).

In summary, these researchers said ‘When cancer prevention is largely considered in a non-communicable disease context, there is a crucial need for resources directed towards cancer prevention programs that target infection, particularly in high-risk populations.’

‘Such interventions can markedly reduce the increasing cancer burden and associated mortality.’

This study was funded by the International Agency for Research on Cancer. The funder of the study had no role in study design, data collection, data analysis, data interpretation, or writing of the report. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication.

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