A recent study published in The Lancet Oncology reveals that infections play a significant role in cancer development, contributing to one in eight new cancer cases globally. The International Agency for Research on Cancer (IARC) conducted the research, linking approximately 2.3 million new cancer cases in 2024 to various infectious agents.
Among the infections identified, Helicobacter pylori was responsible for the largest number of cancer cases worldwide, predominantly in eastern Asia, where it is associated with an increased risk of stomach cancer, totaling 760,000 cases. Human papillomavirus (HPV) followed closely behind, contributing to nearly 750,000 new cancer cases globally, with high rates in sub-Saharan Africa.
The study also expanded the list of cancers linked to infections, including 16 additional types. Notable findings included the association of HIV with cervical cancer and Merkel cell polyomavirus with skin cancer. Epstein-Barr virus, previously underestimated, was linked to around 260,000 cancer cases globally in 2024, leading to various types of cancers, including nasopharyngeal cancer and Hodgkin’s lymphoma.
The report underscored significant regional differences in cancer burden due to infections, with high-income countries benefiting from established screening and vaccination programs. In North America, Helicobacter pylori and HPV are the primary infections contributing to cancer cases.
In Canada, a 2019 study estimated that infections account for four per cent of cancer cases, with more than 7,000 cancer diagnoses annually attributed to these infections. Notable efforts in Canada include robust childhood vaccination programs against HPV. However, concerns arise as cervical cancer rates plateau, jeopardizing the goal of eliminating cervical cancer by 2040.
The key infection leading to cancer cases in Canada is Helicobacter pylori, associated with gastric cancers. Dr. Paul Moayyedi from McMaster University advocates for universal screening programs to detect and treat the bacterium, emphasizing the importance of early intervention to prevent stomach cancer-related deaths.
While infections may not always be top of mind in cancer prevention, advancements in understanding their role in cancer development highlight the importance of proactive measures, such as screening and vaccination programs, to reduce the global burden of infection-related cancers.