A recent study published in The Lancet Oncology reveals that infections play a significant role in causing cancer, with approximately one in eight new cancer cases worldwide linked to various infectious agents. The research, conducted by The International Agency for Research on Cancer (IARC), part of the World Health Organization, estimates that in 2024, infections were responsible for around 2.3 million new cancer cases, representing 12% of all new cases.
The study identified Helicobacter pylori as the primary culprit, contributing to 760,000 cases of stomach cancer, mainly in eastern Asia. Human papillomavirus (HPV) closely followed, causing nearly 750,000 new cancer cases globally, with high prevalence 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, including associations with HIV, cervical cancer, and Merkel cell polyomavirus, a rare virus leading to aggressive skin cancer. Epstein-Barr virus (EBV) was identified as a key player, linked to 260,000 cancer cases globally, such as nasopharyngeal cancer and Hodgkin’s lymphoma.
The research emphasized the importance of recognizing the impact of infections on cancer, highlighting disparities in prevention and treatment access between high-income and lower-resourced countries. In North America, while the burden of cancer-causing infections is lower, H. pylori and HPV remain common sources.
In Canada, a 2019 study led by epidemiologist Karena Volesky estimated that infections account for 4% of cancer cases, leading to over 7,000 cancer diagnoses annually. Elizabeth Holmes, the director of health policy at the Canadian Cancer Society, emphasized the importance of vaccination programs in preventing HPV-related cervical cancer and the need to enhance screening rates to achieve the goal of eliminating cervical cancer by 2040.
Dr. Paul Moayyedi, a gastroenterologist at McMaster University, highlighted the impact of H. pylori on stomach 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 potential benefits of targeted screening programs, particularly for high-risk groups like those with a family history of stomach cancer or indigenous communities.
Overall, the study underscores the significant role of infections in cancer development and the importance of tailored prevention strategies to reduce the global burden of infection-related cancers.
