A recent study published in The Lancet Oncology reveals that infections contribute to a significant number of cancer cases globally. The research, conducted by The International Agency for Research on Cancer (IARC), shows that approximately 12% of new cancer cases in 2024, totaling 2.3 million cases, are linked to various infectious agents.
The bacterium Helicobacter pylori is identified as the leading cause of cancer cases attributed to infections, particularly in eastern Asia, where it contributes to 760,000 cases of stomach cancer. Human papillomavirus (HPV) is another significant infectious agent, responsible for nearly 750,000 new cancer cases worldwide, with high prevalence in sub-Saharan Africa.
The study expands the list of cancers associated with infections to include 16 additional types. Researchers emphasize the growing recognition of the role of Epstein-Barr virus (EBV), which was linked to around 260,000 cases globally in 2024, leading to nasopharyngeal cancer, certain gastric cancers, and Hodgkin’s lymphoma.
Gary Clifford, a co-author of the study and cancer epidemiologist, highlights the evolving understanding of infectious agents’ role in cancer development, emphasizing the need for preventive measures. The study also identifies new infectious agents like HIV and Merkel cell polyomavirus, shedding light on their potential to cause cancer.
The report underscores regional disparities in cancer cases driven by historical factors, with high-income countries showing better outcomes due to established screening and vaccination programs. In North America, Helicobacter pylori and HPV are identified as common sources of cancer-causing infections.
In Canada, a 2019 study led by epidemiologist Karena Volesky estimates that infections account for four percent of cancer cases. While the prevalence of these infections is lower in Canada, they still contribute to over 7,000 cancer diagnoses annually.
Elizabeth Holmes, the director of health policy at the Canadian Cancer Society, expresses concerns about the plateauing rates of cervical cancer in Canada, stressing the importance of vaccination and screening programs. The Canadian cervical cancer elimination plan aims to boost vaccination and screening rates to combat HPV-related cancers effectively.
Dr. Paul Moayyedi, a gastroenterologist, advocates for universal screening programs for Helicobacter pylori to detect and treat stomach cancer early. He emphasizes the potential benefits of targeted screening for high-risk groups to reduce the burden of stomach cancer, especially among vulnerable populations.
