A recent study published in The Lancet Oncology revealed that infections are responsible for one in eight cancer cases globally, accounting for an estimated 2.3 million new cases in 2024. The research, conducted by experts from The International Agency for Research on Cancer (IARC), identified various infectious agents like viruses, bacteria, and other microbes as significant contributors to cancer development.
Among the infections highlighted in the study, Helicobacter pylori stood out as a major culprit, leading to approximately 760,000 cases of stomach cancer, particularly prevalent in eastern Asia. Human papillomavirus (HPV) was also a significant factor, responsible for nearly 750,000 new cancer cases worldwide, with high incidences in sub-Saharan Africa. Additionally, hepatitis B virus (HBV) and hepatitis C virus (HCV) were linked to a considerable number of liver cancer cases.
The research team expanded the list of cancers associated with infections, identifying 16 additional ones. Notably, new findings showed the association of HIV with cervical cancer and a rare virus called Merkel cell polyomavirus with aggressive skin cancer development.
The study methodology involved examining cancer-causing infections, calculating the fraction of cancers attributed to specific agents, and applying these calculations to global cancer databases. Epstein-Barr virus (EBV) also gained recognition for its role in causing cancers like nasopharyngeal cancer, some gastric cancers, and Hodgkin’s lymphoma, contributing to approximately 260,000 cases globally in 2024.
The report emphasized regional disparities in cancer burden, with high-income countries implementing effective screening and vaccination programs compared to lower-resourced regions. In North America, infections like H. pylori and HPV were identified as primary cancer sources.
In Canada, a 2019 study led by epidemiologist Karena Volesky estimated that infections accounted for four percent of cancer cases. Despite lower prevalence rates, these infections were linked to over 7,000 cancer diagnoses annually. HPV vaccination programs in Canada have led to declining cervical cancer rates, but concerns arise over stagnant rates potentially impeding the goal of eliminating cervical cancer by 2040.
Promoting vaccination and screening programs is crucial in combating cancer-causing infections. Dr. Paul Moayyedi from McMaster University emphasized the importance of universal screening for Helicobacter pylori to prevent stomach cancer, particularly among high-risk groups. Enhancing awareness and access to preventive measures are vital steps towards reducing the global burden of infection-related cancers.