A recent study published in The Lancet Oncology reveals that infections play a more significant role in cancer development than previously thought, accounting for one in eight cancer cases globally. The International Agency for Research on Cancer (IARC) found that approximately 2.3 million new cancer cases in 2024, representing 12% of all new cases, were linked to various infectious agents.
Among these agents, Helicobacter pylori was identified as the leading cause of cancer cases globally, particularly stomach cancer, contributing to 760,000 cases, primarily in eastern Asia. Human papillomavirus (HPV) followed closely, responsible for 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 associated with a significant number of liver cancer cases.
The study expanded the list of cancers linked to infections, including 16 additional types, highlighting the evolving scientific understanding of infectious agents’ role in cancer development. Noteworthy findings included the association of HIV with cervical cancer and Merkel cell polyomavirus with aggressive skin cancer.
Researchers calculated the fraction of cancers attributable to specific infections and applied these estimates to global cancer databases to determine the impact of infections on cancer cases. Epstein-Barr virus (EBV) was recognized as a significant contributor to cancer cases globally, associated with about 260,000 cases in 2024, leading to nasopharyngeal cancer, gastric cancers, and Hodgkin’s lymphoma.
In Canada, a 2019 study estimated that infections contribute to 4% of cancer cases, resulting in over 7,000 cancer diagnoses annually. While the prevalence of infection-related cancers is lower in Canada, ongoing monitoring and prevention efforts are essential. HPV vaccination programs have played a crucial role in reducing cervical cancer rates in Canada, but recent data suggests a plateau in progress, raising concerns about meeting elimination targets by 2040. Efforts to increase vaccination and screening rates are crucial for achieving these goals.
Helicobacter pylori remains a significant concern for cancer development, particularly stomach cancer, with notable impacts in eastern Asia. Screening programs for high-risk populations, such as those with a family history of stomach cancers or specific communities, could help identify and treat infections early, potentially saving lives.