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 International Agency for Research on Cancer (IARC) found that roughly 2.3 million new cancer cases, representing 12% of all cases, were linked to various infectious agents such as viruses, bacteria, and other microbes.
Among the infectious agents, the bacterium Helicobacter pylori was identified as the leading cause of cancer cases globally, particularly contributing to 760,000 cases of stomach cancer, mainly in eastern Asia. Human papillomavirus (HPV) followed closely behind, responsible for nearly 750,000 new cancer cases globally, including cervical cancer and other types of cancers, with high prevalence in sub-Saharan Africa.
Furthermore, 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 by identifying 16 additional types of cancers.
The research highlighted the evolving understanding of infectious agents as cancer-causing factors, with new discoveries such as the link between HIV and cervical cancer, and Merkel cell polyomavirus’s role in skin cancer. Epstein-Barr virus (EBV) was recognized as a key player in various cancers globally, including nasopharyngeal cancer, gastric cancers, and Hodgkin’s lymphoma.
The study emphasized the regional disparities in cancer burden due to infections, with high-income countries benefiting from established screening and vaccination programs compared to lower-resourced regions. In North America, Helicobacter pylori and HPV were identified as the primary sources of cancer-causing infections.
In Canada, a study led by epidemiologist Karena Volesky estimated that infections contribute to four percent of cancer cases, translating to over 7,000 cancer diagnoses annually. While Canada has lower infection rates compared to other regions, efforts to increase vaccination rates and screening programs, particularly for HPV, are crucial in cancer prevention.
Dr. Paul Moayyedi from McMaster University highlighted the importance of screening for Helicobacter pylori, especially in high-risk groups. He advocated for universal screening programs to detect and treat the bacterium, emphasizing the potential to save lives through early intervention.
In conclusion, the study underscores the significant impact of infections on global cancer incidence, urging continued efforts in prevention, screening, and treatment to reduce the burden of infection-related cancers.