A recent study in The Lancet Oncology reveals that infections play a significant role in causing cancer, contributing to one in eight new cancer cases globally. The research, conducted by The International Agency for Research on Cancer (IARC), identified microbes like viruses and bacteria as culprits behind an estimated 2.3 million new cancer cases in 2024.
Among the infectious agents, Helicobacter pylori topped the list, leading to 760,000 cases, particularly in eastern Asia where it raises the risk of stomach cancer. Human papillomavirus (HPV) followed closely, causing nearly 750,000 new cancer cases worldwide, with high prevalence in sub-Saharan Africa. Hepatitis B virus (HBV) and hepatitis C virus (HCV) were also linked to a substantial number of liver cancer cases.
Furthermore, the study expanded the list of cancers linked to infections, adding 16 additional types. Researchers highlighted the growing evidence of certain infections like HIV and Merkel cell polyomavirus in causing cancer. Epstein-Barr virus (EBV) was also recognized as a significant contributor, associated with various cancers globally.
The study emphasizes regional disparities in cancer rates, influenced by historical differences in access to prevention and treatment. While high-income countries with established screening and vaccination programs fare better, lower-resourced regions face challenges in cancer management.
In Canada, a 2019 study led by epidemiologist Karena Volesky estimated that four percent of cancers are attributable to infections, translating to over 7,000 cancer diagnoses annually. Despite lower infection rates in Canada, vigilance against infections like HPV remains crucial for cancer prevention.
Notably, Helicobacter pylori stands out as a major cause of stomach cancer, with McMaster University’s Dr. Paul Moayyedi advocating for universal screening programs to detect and treat the bacterium early. Screening programs could be particularly beneficial for high-risk groups, such as those with a family history of stomach cancer or specific communities.
In conclusion, the study underscores the impact of infections on cancer incidence globally and the importance of targeted interventions and screenings to reduce the burden of infection-related cancers.