A recent study published in The Lancet Oncology reveals that infections play a significant role in causing cancer, with approximately one in eight cancer cases worldwide linked to various infectious agents. The International Agency for Research on Cancer (IARC) conducted the research, identifying an estimated 2.3 million new cancer cases in 2024 attributable to infections, accounting for 12% of all new cases.
Among the infectious agents, Helicobacter pylori, a bacterium known to increase the risk of stomach cancer, was found to be responsible for the largest number of cancer cases globally, with 760,000 cases primarily in eastern Asia. Human papillomavirus (HPV) followed closely behind, contributing to nearly 750,000 new cases globally, particularly in sub-Saharan Africa. Hepatitis B virus (HBV) and hepatitis C virus (HCV) were also associated with a significant number of liver cancer cases.
The study expanded the list of cancers linked to infections, including 16 additional types. New findings highlighted the role of Epstein-Barr virus (EBV), which was linked to around 260,000 cases globally in 2024, leading to diseases such as nasopharyngeal cancer, certain gastric cancers, and Hodgkin’s lymphoma. The research also identified HIV as a new infectious agent linked to cervical cancer and Merkel cell polyomavirus as a rare virus associated with aggressive skin cancer.
Researchers calculated the fraction of cancer cases attributable to specific infections by examining global databases of new cancer cases. The study emphasized the impact of regional disparities, with high-income countries that implemented cancer screening and vaccination programs showing better outcomes compared to lower-resource nations.
In Canada, a 2019 study estimated that infections accounted for 4% of cancer cases, leading to over 7,000 cancer diagnoses annually. Notably, HPV remains a focus in Canada, with efforts to increase vaccination rates and screening to combat cervical cancer. Although cervical cancer rates had been decreasing in Canada due to vaccination programs, recent plateaus raise concerns about meeting elimination goals.
Helicobacter pylori, a bacterium associated with gastric cancers, poses a significant health risk globally, with Dr. Paul Moayyedi from McMaster University advocating for universal screening programs to detect and treat the bacterium, potentially saving lives. Moayyedi emphasized the importance of screening high-risk individuals, such as those with a family history of stomach cancers or specific communities, to address the impact of infections in cancer development.
The study underscores the importance of understanding the role of infections in cancer incidence and the need for targeted interventions to reduce the burden of infection-related cancers globally.