One in Eight Cancers Worldwide Linked to Preventable Infections: IARC Report

Approximately one in eight cancer cases globally, representing approximately 2.3 million new diagnoses, is linked to infections caused by viruses, bacteria, and parasites according to an evaluation published in The Lancet Oncology on September 28, 2026, by the International Agency for Research on Cancer (IARC). In an analysis released by the Lyon-based World Health Organization agency, researchers established that twelve recognized carcinogenic agents drive this portion of the global cancer burden, with five specific pathogens accounting for virtually all infection-attributable malignancies.

The Global Burden of 2.3 Million Infection-Linked Cancers in 2024

The updated assessment from the International Agency for Research on Cancer (IARC)—an evaluation published in The Lancet Oncology—revises previous global metrics by analyzing 12 distinct biological agents across datasets for 2024. While overall annual cancer diagnoses hover near 20 million globally, the proportion driven by infectious pathogens highlights a preventable etiology. Dr. Gary Clifford, co-principal author of the study, noted in an agency statement that the patterns of infection-related cancers continue to change as scientific knowledge progresses.

The biological pathogenesis behind these statistics involves inflammation. As explained by Dr. Vincent Valinducq on TF1 Info, when a virus, bacterium, or parasite establishes long-term residency within the body, it can provoke inflammation and sometimes mutations that can lead to cancer.

Pathogen Rankings Led by Helicobacter pylori and Human Papillomavirus

Five specific infectious agents concentrate the vast majority of the 2.3 million infection-linked cancer cases. Leading the global tabulation is the gastric bacterium Helicobacter pylori, which is responsible for approximately 760,000 cases, primarily presenting as cancers of the stomach. The bacterium colonizes the stomach—often acquired during childhood—and remains asymptomatic, infecting more than 50% of individuals over the age of 50 in France.

Human papillomavirus (HPV) ranks second, driving roughly 750,000 cancer cases worldwide. HPV causes cervical malignancies as well as cancers of the anus, throat, and other regional sites. Following these two primary drivers are the hepatitis B virus (VHB), accountable for 360,000 cases of liver cancer; the Epstein-Barr virus (EBV), linked to 260,000 cases including nasopharyngeal carcinomas, lymphomas, and stomach cancers; and the hepatitis C virus (VHC), responsible for 160,000 liver cancer diagnoses. The inclusion of EBV and the human immunodeficiency virus (HIV) within the updated IARC matrix reflects newly established links between infections and cancers, notably the link between EBV and stomach cancer.

East Asia and Sub-Saharan Africa Lead Infection-Linked Cancers

The distribution of infection-driven malignancies shows geographic inequality. East Asia alone concentrates 42% of the global total, driven heavily by Helicobacter pylori and chronic hepatitis B infections. Meanwhile, sub-Saharan Africa accounts for 28.5% of these cases, driven largely by human papillomavirus and Kaposi sarcoma-associated herpesvirus.

More than three-quarters of all infection-linked cancers occur in low- and middle-income nations. In these regions, health systems face structural, financial, and political barriers that restrict routine deployment of preventative interventions, diagnostic screenings, and treatments.

Vaccines and Screening Programs Could Prevent Most Cancers

The majority of these 2.3 million cancers could be avoided through established public health interventions, according to Dr. Harriet Rumgay, an IARC scientist and co-author of the study. Primary prevention relies on immunization programs, specifically vaccines targeting HPV and hepatitis B.

Secondary prevention protocols require widespread diagnostic screening and treatment. For Helicobacter pylori, screening and treatment can reduce the burden. Similarly, screening programs for HPV-related cancers, such as smears and HPV tests, are available. However, significant clinical gaps remain. For viral pathogens such as Epstein-Barr, no effective prophylactic vaccines currently exist, leaving researchers calling for investment in new prevention tools.

Disclaimer: The information provided in this article is for educational and scientific communication purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider regarding any medical condition, diagnosis, or treatment plan.