A recent study published in The Lancet Oncology reveals that infections play a more significant role in causing cancer than previously thought. Researchers at The International Agency for Research on Cancer (IARC) found that approximately 2.3 million new cancer cases in 2024, equivalent to 12% of all new cases worldwide, were linked to infectious agents such as viruses and bacteria.
Among the infectious agents, Helicobacter pylori was identified as the leading cause of cancer cases globally, particularly in eastern Asia, contributing to 760,000 cases of stomach cancer. Human papillomavirus (HPV) followed closely behind, responsible for nearly 750,000 new cases globally, with high prevalence in sub-Saharan Africa.
The study also expanded the list of cancers linked to infections, including 16 additional types. Notably, Epstein-Barr virus (EBV) was associated with around 260,000 cancer cases globally in 2024, leading to nasopharyngeal cancer, certain gastric cancers, and Hodgkin’s lymphoma.
Infections like HIV and Merkel cell polyomavirus were also identified as cancer-causing agents. The research methodology involved analyzing the role of infections in cancer development and calculating the fraction of cancer cases attributable to specific infectious agents.
The report emphasizes regional disparities in cancer burden, with higher-income countries having better prevention and treatment programs compared to lower-resourced regions. In North America, Helicobacter pylori and HPV were identified as the primary sources of cancer-causing infections.
In Canada, a 2019 study led by epidemiologist Karena Volesky estimated that infections contribute to around 4% of cancer cases. While the prevalence of these infections is lower in Canada, they still result in over 7,000 cancer diagnoses annually.
Health experts in Canada stress the importance of HPV vaccination to prevent cervical cancer. Despite declining rates due to vaccination programs, concerns arise over a recent plateau in progress towards eliminating cervical cancer by 2040.
Efforts are being made to increase vaccination and screening rates in Canada, aiming for a more comprehensive approach to combat cancer-causing infections. Screening programs for high-risk individuals, such as those with a family history of specific cancers, are being recommended to enhance early detection and save lives.
