A recent study published in The Lancet Oncology reveals that infections are responsible for one in eight cancer cases globally. The research, led by experts at The International Agency for Research on Cancer (IARC), identified approximately 2.3 million new cancer cases in 2024 linked to various infectious agents, comprising 12% of all new cancer diagnoses.
Among the infectious agents, Helicobacter pylori, a bacterium associated with stomach cancer, accounted for 760,000 cases, primarily in eastern Asia. Human papillomavirus (HPV) was another significant contributor, causing nearly 750,000 new cancer cases worldwide, particularly in sub-Saharan Africa. Hepatitis B virus (HBV) and hepatitis C virus (HCV) were also implicated in a substantial number of liver cancer cases.
The study expanded the list of cancers linked to infections, identifying 16 additional types. Notably, new evidence emerged linking HIV to cervical cancer and Merkel cell polyomavirus to a severe form of skin cancer.
Epstein-Barr virus (EBV) was highlighted as a key player, contributing to about 260,000 cancer cases globally in 2024, including nasopharyngeal cancer, some gastric cancers, and Hodgkin’s lymphoma. The study emphasized the need to address EBV-related health burdens, which extend beyond cancer to conditions like multiple sclerosis.
Regional disparities were noted in the report, with high-income nations benefiting from established cancer screening and vaccination programs compared to lower-resourced countries. In North America, infections like H. pylori and HPV are major cancer risk factors, although the overall burden is lower than in other regions.
In Canada, a 2019 study estimated that infections account for four percent of cancer cases. The research, conducted by epidemiologist Karena Volesky at McGill University, highlighted the importance of understanding the impact of infectious agents on cancer incidence.
Public health experts in Canada are particularly vigilant about HPV due to its association with cervical cancer. Despite successful vaccination programs, concerns have been raised about plateauing cervical cancer rates, emphasizing the need for sustained prevention efforts.
Helicobacter pylori remains a significant concern, with McMaster University researcher Dr. Paul Moayyedi advocating for universal screening programs to detect and treat the bacterium, which is linked to gastric cancers. While stomach cancers may not receive as much attention as other cancer types, targeted screening initiatives for high-risk groups could lead to early detection and improved outcomes.