A recent study published in The Lancet Oncology suggests that infections play a more significant role in cancer development than previously thought. The research, conducted by The International Agency for Research on Cancer (IARC), revealed that approximately one in eight new cancer cases worldwide can be attributed to various viruses, bacteria, and other microbes.
The study highlighted that in 2024, an estimated 2.3 million new cancer cases, representing 12% of all new cases, were linked to infectious agents. The bacterium Helicobacter pylori was identified as the leading cause of cancer cases globally, particularly in eastern Asia, where it accounted for 760,000 cases of stomach cancer. Human papillomavirus (HPV) followed closely, contributing to nearly 750,000 new cancer cases, with high prevalence in sub-Saharan Africa.
Furthermore, hepatitis B virus (HBV) and hepatitis C virus (HCV) were associated with a significant number of liver cancer cases. The study also expanded the list of cancers linked to infections, including identifying HIV’s connection to cervical cancer and Merkel cell polyomavirus’s role in skin cancer.
Researchers calculated the fraction of cancer cases linked to specific infections by analyzing global databases of new cancer cases. Epstein-Barr virus (EBV) was recognized as a significant contributor to cancer, with around 260,000 cases worldwide in 2024, leading to various types of cancer such as nasopharyngeal cancer and Hodgkin’s lymphoma.
The study emphasized regional disparities in cancer rates, with high-income countries benefiting from established screening and vaccination programs compared to lower-resourced nations. Despite the progress in some regions, challenges remain in implementing effective prevention and treatment strategies globally.
In Canada, a 2019 study estimated that infections account for four percent of cancer cases, leading to over 7,000 cancer diagnoses annually. The study highlighted the importance of monitoring infections like HPV in Canada and the need to enhance vaccination and screening efforts to combat cervical cancer effectively.
Dr. Paul Moayyedi from McMaster University emphasized the impact of Helicobacter pylori in causing stomach cancer, urging for universal screening programs to detect and treat the bacterium early. While stomach cancer may not receive as much attention as other cancer types, targeted screening programs for high-risk groups could significantly reduce mortality rates.
Overall, the study underscores the critical role of infections in cancer development and the importance of tailored prevention and treatment strategies to combat these preventable causes of cancer.