A recent study published in The Lancet Oncology reveals that infections play a larger role in cancer development than previously thought, contributing to one in eight new cancer cases worldwide. The International Agency for Research on Cancer (IARC) conducted the research, linking an estimated 2.3 million new cancer cases in 2024 to infectious agents.
The study identified various viruses, bacteria, and other microbes as significant contributors to cancer. The bacterium Helicobacter pylori was responsible for a substantial number of stomach cancer cases, totaling 760,000 instances, primarily in eastern Asia. Human papillomavirus (HPV) was another prominent infectious agent, causing nearly 750,000 new cancer cases globally, particularly in sub-Saharan Africa.
Researchers expanded the list of cancers linked to infections, adding 16 additional types for the first time. They highlighted the increased understanding of the cancer-causing potential of certain infections, including HIV’s association with cervical cancer and Merkel cell polyomavirus’s role in skin cancer.
The study methodology involved identifying infectious agents linked to cancer, calculating the fraction of cancers attributable to specific infections, and applying these calculations to global databases of new cancer cases. Epstein-Barr virus (EBV) was noted as a significant factor in nasopharyngeal cancer, some gastric cancers, and Hodgkin’s lymphoma, contributing to around 260,000 cases globally in 2024.
The report emphasized regional disparities in cancer rates, with high-income countries that have robust screening and vaccination programs faring better than lower-resourced nations. In North America, Helicobacter pylori and HPV are predominant cancer-causing infections.
In Canada, a 2019 study led by epidemiologist Karena Volesky estimated that infections account for four percent of cancer cases. Despite lower infection prevalence in Canada, these infections still lead to over 7,000 cancer diagnoses annually. Efforts to combat HPV-related cancers, such as increasing vaccination rates and screening, are crucial to reducing cancer incidence.
Dr. Paul Moayyedi from McMaster University emphasized the importance of screening for Helicobacter pylori, which is associated with stomach cancer. While this form of cancer may not receive as much attention as others, targeted screening programs for high-risk groups could significantly impact cancer prevention and save lives.