A recent study published in The Lancet Oncology reveals that infections play a significant role in causing cancer, with one in eight cases worldwide linked to various viruses, bacteria, and other microbes. The research, conducted by The International Agency for Research on Cancer (IARC), highlighted that infections were responsible for around 2.3 million new cancer cases in 2024, representing 12% of all new cases reported globally.
The study identified Helicobacter pylori as the primary culprit, contributing to 760,000 cases of stomach cancer, particularly prevalent in eastern Asia. Human papillomavirus (HPV) followed closely, with nearly 750,000 new cases reported globally, mainly affecting regions like sub-Saharan Africa. Additionally, hepatitis B virus (HBV) and hepatitis C virus (HCV) were associated with a substantial number of liver cancer cases.
Researchers expanded the list of cancers linked to infections, identifying 16 additional types affected. Gary Clifford, a co-author of the study and cancer epidemiologist based in Lyon, France, emphasized the evolving understanding of infectious agents as cancer causes.
Notable findings included the association of HIV with cervical cancer and Merkel cell polyomavirus with a rare form of skin cancer. The study methodology involved evaluating cancer-causing infections, calculating their impact on specific cancers, and applying these findings to global cancer databases.
The research shed light on the significant role of Epstein-Barr virus (EBV) in causing various cancers globally, including nasopharyngeal cancer, certain gastric cancers, and Hodgkin’s lymphoma. The study underscored the need for increased awareness and prevention efforts, particularly in regions with limited access to healthcare services.
In Canada, a 2019 study estimated that infections accounted for approximately four percent of cancer cases, leading to over 7,000 diagnoses annually. Researchers emphasized the importance of understanding the impact of infections on cancer development and the necessity of preventive measures such as vaccination programs.
While Canada has made progress in reducing cervical cancer rates through vaccination initiatives, there are concerns about recent plateaus in these efforts. Efforts to increase vaccination and screening rates are crucial to achieving the goal of eliminating cervical cancer by 2040.
The study highlighted regional disparities in cancer cases attributed to infections, with higher-income countries showing better outcomes due to established prevention programs. Implementing effective strategies globally remains a priority to reduce the burden of infections on cancer incidence and mortality rates.