Most of the more than 2 million cases of infection-associated cancer were attributable to Helicobacter pylori, human papillomavirus, Epstein-Barr virus and hepatitis B and C.
An estimated 2.3 cancer cases worldwide—or one in eight—are attributable to infections, according to study results published in The Lancet Oncology. Fortunately, infection-related malignancies are largely preventable through vaccination and treatment of underlying diseases.
“This recent Lancet data is a profound reminder that a significant portion of our global cancer burden is fundamentally preventable,” David Greenberg, MD, of Hackensack Meridian Jersey Shore University Medical Center, said in a news release. “We have historically siloed infectious diseases and oncology, but they are deeply intertwined. By shifting our focus toward aggressive infection control, we can literally vaccinate and treat our way out of millions of future cancer diagnoses.”
Harriet Rumgay, PhD, of the World Health Organization’s International Agency for Research on Cancer, and colleagues used data from the Global Cancer Observatory’s Cancer Today database (GLOBOCAN) to estimate the number, proportion and incidence of cancers attributable to 12 infections classified as carcinogenic.
Chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infection can cause liver scarring, cirrhosis and liver cancer. Hepatitis B is preventable with a vaccine and can be treated with antiviral medications, but they usually do not lead to a cure. In contrast, there is no vaccine for hepatitis C, but more than 90% of patients can be cured with direct-acting antivirals taken for two or three months.
Helicobacter pylori is the most common bacterial cause of cancer. It causes gastric ulcers and can trigger stomach cancer, a rare type of lymphoma and possibly colorectal cancer. H. pylori, which is transmitted via saliva and contaminated food or water, is more common in lower-income countries, and most people are infected during childhood. It can be treated with antibiotics and medications that reduce stomach acid.
Epstein-Barr virus (EBV) is a common herpesvirus that causes mononucleosis. It persists in the body and can trigger nasopharyngeal cancer, certain types of lymphoma and stomach cancer. More than 90% of adults have evidence of EBV infection, which usually occurs during childhood. There is no vaccine or approved antiviral treatment.
HIV is classified as a carcinogenic virus. People with advanced HIV disease can develop AIDS-defining cancers, such as Kaposi sarcoma and non-Hodgkin lymphoma, but even people on antiretroviral treatment with well controlled HIV are at higher risk for multiple malignancies.
Kaposi-sarcoma-associated herpesvirus (HHV-8) is another common herpesvirus. It usually does not lead to illness in healthy people, but it can cause tumors of the skin, mucous membranes and internal organs in people with compromised immunity.
The other infectious agents included in the analysis are human T-cell lymphotropic virus, Merkel cell polyomavirus, Schistosoma haematobium (a parasitic worm that can cause bladder cancer) and two parasitic liver flukes, Opisthorchis viverrine and Clonorchis sinensis, that can cause liver and bile duct cancer.
The study found that an estimated 2.3 million new cancer cases were attributable to infections globally in 2024, equivalent to 12% of all cancer cases. Of these, the largest number (760,000 cases, or 4%) were caused by H. pylori, followed by HPV (750,000 cases, or 4%), HBV (360,000 cases, or 2%), EBV (260,000 cases, or 1%) and HCV (160,000 cases).
More than three quarters of infection-attributable cancers occurred in low- and middle-income countries. Eastern Asian had the largest burden, with 990,000 cases (42% of the global total). Rates were also higher than the global average in sub-Saharan Africa, Central and Eastern Europe and Southeast Asia.
“Our findings highlight the importance of infection control to achieve cancer prevention,” the study authors concluded. “Scientifically proven, but often underused, approaches include HPV and HBV vaccination; testing and treatment of HIV, H pylori, HBV and HCV; safe injection practices; access to condoms and pre-exposure prophylaxis [PrEP] to prevent HIV transmission; and screening of precancerous lesions for HPV-driven cervical and anal cancer. Our findings also inform the investment cases for research and development for new prevention tools, most notably for EBV.”