New study findings suggest that infections are responsible for one in eight cancer cases globally, a significant factor often overlooked compared to sun exposure, smoking, and family history. The Lancet Oncology published a paper revealing that approximately 2.3 million new cancer cases in 2024, equivalent to 12% of all cases, were linked to various infectious agents including viruses and bacteria.
Research conducted by The International Agency for Research on Cancer (IARC), a branch of the World Health Organization, identified the bacterium Helicobacter pylori as the leading cause of cancer cases globally, particularly in eastern Asia where it contributed to 760,000 cases of stomach cancer. Human papillomavirus (HPV) was the second most common infectious agent, accounting for nearly 750,000 new cancer cases worldwide, predominantly in sub-Saharan Africa.
The study expanded the list of cancers linked to infections, adding 16 more types to the existing ones. Notable findings included the role of Epstein-Barr virus (EBV) in causing about 260,000 cases globally, associated with nasopharyngeal cancer, some gastric cancers, and Hodgkin’s lymphoma.
Additionally, new infectious agents like HIV and Merkel cell polyomavirus were identified as cancer-causing, with HPV being a major concern in Canada. Elizabeth Holmes from the Canadian Cancer Society highlighted the importance of vaccination programs to combat HPV-related cervical cancer, emphasizing the need to increase vaccination and screening rates to achieve the goal of eliminating cervical cancer by 2040.
In Canada, a 2019 study estimated that four percent of cancer cases were attributable to infections, leading to over 7,000 cancer diagnoses annually. Dr. Paul Moayyedi from McMaster University advocated for universal screening programs for Helicobacter pylori, the bacterium primarily responsible for gastric cancers, emphasizing the importance of early detection and treatment to prevent adverse outcomes.
Overall, the study underscores the significant impact of infections on global cancer rates and emphasizes the necessity of preventive measures and access to treatment, particularly in regions with limited resources.