A recent study published in The Lancet Oncology revealed that infections play a significant role in cancer development, accounting for one in eight new cancer cases worldwide in 2024. The research conducted by The International Agency for Research on Cancer (IARC), a branch of the World Health Organization, identified various microbes, including viruses and bacteria, as culprits behind an estimated 2.3 million new cancer diagnoses.
Among the infections, Helicobacter pylori, a bacterium prevalent in eastern Asia, was linked to 760,000 stomach cancer cases. Human papillomavirus (HPV) followed closely, causing nearly 750,000 cancer cases globally, with high occurrences in sub-Saharan Africa. Hepatitis B virus (HBV) and hepatitis C virus (HCV) were also associated with a significant number of liver cancer cases.
Furthermore, the study expanded the list of cancers linked to infections, identifying 16 additional types. Notably, Epstein-Barr virus (EBV) was found to be responsible for about 260,000 cases globally in 2024, contributing to nasopharyngeal cancer, certain gastric cancers, and Hodgkin’s lymphoma.
Researchers emphasized the evolving understanding of infectious agents’ impact on cancer development, highlighting new findings such as the association between HIV and cervical cancer and the role of Merkel cell polyomavirus in skin cancer. The report underscored regional disparities in cancer burden, with higher-income countries exhibiting better outcomes due to established screening and vaccination programs.
In Canada, a 2019 study led by epidemiologist Karena Volesky from McGill University estimated that infections contribute to four percent of cancer cases. Despite lower infection prevalence, these infections still lead to over 7,000 cancer diagnoses annually.
Elizabeth Holmes, the director of health policy at the Canadian Cancer Society, expressed concerns about plateauing cervical cancer rates in Canada, emphasizing the importance of vaccination programs. The Canadian cervical cancer elimination plan aims to boost vaccination and screening rates to combat HPV-related cancers effectively.
Dr. Paul Moayyedi, a gastroenterologist at McMaster University, highlighted the impact of Helicobacter pylori on gastric cancer, advocating for universal screening programs to detect and treat the bacterium early. While stomach cancer may not receive as much attention as other cancers, Moayyedi stressed the importance of targeted screening programs for high-risk groups to prevent unnecessary deaths.
The study’s findings shed light on the crucial role of infections in cancer development and the need for continued efforts to implement effective prevention and treatment strategies worldwide.