A recent study published in The Lancet Oncology reveals that infections are responsible for one in eight cancer cases worldwide, challenging common beliefs about cancer risk factors. The research, conducted by The International Agency for Research on Cancer (IARC), part of the World Health Organization, identified approximately 2.3 million new cancer cases in 2024 linked to infectious agents, comprising 12% of all new cases.
Among the infectious agents, Helicobacter pylori, a bacterium primarily associated with stomach cancer, accounted for 760,000 cases globally, with a concentration in eastern Asia. Human papillomavirus (HPV) followed closely, causing nearly 750,000 new cases worldwide, particularly impacting sub-Saharan Africa. Hepatitis B virus (HBV) and hepatitis C virus (HCV) were also significant contributors to liver cancer cases.
Researchers expanded the list of cancers linked to infections, adding 16 additional types to the existing findings. Notably, new infectious agents like HIV were identified as contributors to cervical cancer, while the Merkel cell polyomavirus was associated with an aggressive form of skin cancer.
The study methodology involved identifying cancer-causing infections, calculating their impact on cancer cases, and applying these calculations to global cancer databases. Epstein-Barr virus (EBV) was highlighted as a key player, causing around 260,000 cases globally in 2024 and linked to cancers such as nasopharyngeal cancer and Hodgkin’s lymphoma.
Regional disparities in cancer cases were attributed to historical differences in access to prevention and treatment. High-income countries with established screening and vaccination programs outperformed lower-resourced regions. In North America, Helicobacter pylori and HPV were the primary culprits of cancer-causing infections.
In Canada, a 2019 study estimated that infections contribute to four percent of cancer cases, with over 7,000 cancer diagnoses annually. The findings underscore the importance of addressing these infections, particularly HPV, to reduce cancer incidence rates. Efforts to increase vaccination and screening rates are crucial to combat cervical cancer effectively.
Despite the progress in cancer prevention, challenges remain in implementing effective strategies globally. Dr. Paul Moayyedi, a leading gastroenterologist, advocates for universal screening programs for Helicobacter pylori to prevent stomach cancer deaths. Screening high-risk groups and promoting awareness among vulnerable populations could significantly impact cancer outcomes.
The study sheds light on the significant role of infections in cancer development, emphasizing the need for comprehensive prevention and treatment strategies to reduce the global burden of infection-related cancers.
