A recent study published by The Lancet Oncology reveals that infections play a more significant role in causing cancer than previously thought. Researchers from The International Agency for Research on Cancer found that approximately 12% of new cancer cases worldwide in 2024, totaling 2.3 million cases, were linked to various viruses, bacteria, and other microbes.
The bacterium Helicobacter pylori was identified as the leading cause of cancer cases globally, particularly stomach cancer, with 760,000 cases, mainly in eastern Asia. Human papillomavirus (HPV) followed closely behind, accounting for nearly 750,000 new cancer cases globally, predominantly in sub-Saharan Africa. Hepatitis B and C viruses 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. Researchers highlighted the increasing evidence of certain infections, such as HIV and Merkel cell polyomavirus, being linked to specific cancers.
Epstein-Barr virus (EBV) was recognized as a key contributor to cancer, with approximately 260,000 cases globally in 2024, associated with nasopharyngeal cancer, some gastric cancers, and Hodgkin’s lymphoma. EBV is also implicated in multiple sclerosis.
The study emphasized regional disparities in cancer cases attributed to infections, with high-income countries benefiting from established screening and vaccination programs. In North America, infections like H. pylori and HPV are common causes of cancer.
In Canada, a 2019 study estimated that infections account for around four percent of cancer cases. While the prevalence of infection-related cancers is lower in Canada, they still lead to over 7,000 cancer diagnoses annually.
Efforts to combat infection-related cancers in Canada include vaccination programs, screening initiatives, and timely follow-up care. However, challenges remain in achieving vaccination and screening targets to reduce the burden of cervical cancer, particularly due to HPV infections.
Dr. Paul Moayyedi, a leading gastroenterologist, advocates for universal screening programs for Helicobacter pylori to prevent stomach cancer deaths. Screening high-risk individuals, such as those with a family history of stomach cancer or in specific communities, could potentially save lives.
Overall, the study underscores the importance of recognizing and addressing infections as significant contributors to the global burden of cancer.
