A recent study published in The Lancet Oncology reveals that infections play a significant role in causing cancer, with one in eight new cancer cases worldwide linked to various viruses, bacteria, and other microbes. The research, conducted by The International Agency for Research on Cancer (IARC), estimates that approximately 2.3 million new cancer cases in 2024, accounting for 12% of all new cases, are attributed to infectious agents.
The study identified Helicobacter pylori as the leading cause of cancer cases globally, particularly in eastern Asia, where it is associated with an increased risk of stomach cancer, contributing to 760,000 cases. Human papillomavirus (HPV) closely followed, accounting for nearly 750,000 new cases worldwide, with high prevalence in sub-Saharan Africa. Additionally, hepatitis B virus (HBV) and hepatitis C virus (HCV) were linked to a considerable number of liver cancer cases.
Researchers expanded their list of infections linked to cancer, identifying 16 additional ones, including HIV’s association with cervical cancer and Merkel cell polyomavirus’s connection to aggressive skin cancer. Epstein-Barr virus (EBV) emerged as a significant contributor to cancer cases globally, with approximately 260,000 cases in 2024, leading to nasopharyngeal cancer, some gastric cancers, and Hodgkin’s lymphoma.
The study underscores regional disparities in cancer rates, with high-income countries benefiting from established screening and vaccination programs. In North America, infections like Helicobacter pylori and HPV are prevalent causes of cancer, albeit at lower rates compared to other regions.
In Canada, a study led by epidemiologist Karena Volesky estimated that infections contribute to about four percent of cancer cases. While the prevalence of these infections is lower in Canada, they still result in over 7,000 cancer diagnoses annually. Efforts to combat HPV-related cervical cancer through vaccination programs have shown progress but face challenges in achieving elimination goals without increased vaccination rates and screening coverage.
Helicobacter pylori remains a concerning bacterium leading to gastric cancers, with efforts to implement universal screening programs to detect and treat the infection. Despite stomach cancers being perceived as lower priority, targeted screening for high-risk groups, such as those with a family history of stomach cancer or specific communities, could significantly impact early detection and save lives.