Study Links 12% of Cancer Cases Worldwide to Infections, Highlighting Major Prevention Opportunities
An estimated 2.3 million new cancer cases worldwide in 2024 were attributable to infections, accounting for approximately 12 per cent of all newly diagnosed cancers, according to a major international study published in The Lancet Oncology. The research, released by the International Agency for Research on Cancer (IARC), highlights how certain bacteria, viruses and other infectious agents contribute to the global cancer burden.
The findings suggest that nearly one in every eight new cancer cases worldwide is linked to an infection. Researchers say the results underscore the importance of vaccination, early diagnosis, screening and effective treatment in preventing cancers associated with infectious diseases.
The study, titled Global Burden of Cancer Attributable to Infections in 2024, provides updated estimates of infection-related cancers across countries and regions. It expands earlier assessments by including additional infectious agents and recently established associations between infections and certain cancer types.
Researchers identified Helicobacter pylori, a bacterium associated with stomach cancer, as the leading contributor, accounting for approximately 760,000 cancer cases worldwide. The bacterium can infect the stomach lining and cause chronic inflammation, increasing the risk of developing cancer over time.
Human papillomavirus (HPV) was the second-largest contributor, accounting for approximately 750,000 cases. HPV is responsible for nearly all cases of cervical cancer and can also cause cancers of the anus, penis, vulva, vagina and parts of the throat.
Hepatitis B virus accounted for an estimated 360,000 cancer cases, primarily through its association with liver cancer. Hepatitis C virus contributed approximately 160,000 cases, while Epstein-Barr virus was linked to around 260,000 cases, including certain lymphomas and stomach cancers.
The researchers also assessed cancers associated with other infectious agents, including HIV and Merkel cell polyomavirus. The findings demonstrate that the relationship between infection and cancer extends beyond a handful of well-known diseases.
The burden of infection-related cancer varied considerably across geographical regions. Eastern Asia recorded approximately 990,000 cases, representing 42 per cent of the worldwide total. Sub-Saharan Africa, Central and Eastern Europe, and Southeast Asia also recorded high rates of infection-attributable cancer relative to their populations.
Differences in infection prevalence, access to healthcare, vaccination coverage, screening programmes and treatment availability help explain these geographical disparities. In many lower-income countries, infectious diseases remain an especially important contributor to cancer because preventive healthcare and early treatment are not consistently accessible.
The study has important implications for India, where infections such as HPV, hepatitis viruses and H. pylori are relevant public-health concerns. Improving access to HPV vaccination, hepatitis B immunisation, appropriate testing and treatment could help reduce the future burden of several cancers.
Cervical cancer prevention is a particularly important area. HPV vaccination can protect against the virus types responsible for most cervical cancers, while screening can identify precancerous changes before they progress to invasive disease. Expanding these services could prevent substantial illness and deaths over time.
Hepatitis B vaccination offers another established prevention strategy, reducing the risk of chronic infection and the liver damage that can eventually lead to cancer. Hepatitis C can be cured in most cases with appropriate antiviral treatment, while H. pylori infection can often be treated with a combination of antibiotics and acid-suppressing medication when clinically indicated.
However, not every infection leads to cancer, and the presence of an infectious agent does not mean that a person will inevitably develop the disease. Cancer risk depends on several factors, including the type and duration of infection, the person’s immune response, genetics, lifestyle and access to medical care.
Researchers emphasise that infection-associated cancers represent an important opportunity for prevention because several of their underlying causes can be addressed through existing public-health measures. Vaccines, diagnostic testing, treatment and screening programmes are already available for some of the most significant cancer-causing infections.
The study also highlights the need for further research into infections for which effective preventive tools remain limited. Epstein-Barr virus, for example, is associated with several cancers, but there is currently no routinely available vaccine to prevent EBV infection.
The findings reinforce a central message for global cancer control: preventing and treating infectious diseases can reduce the number of people who develop cancer. Wider access to proven interventions, particularly in regions with the highest disease burden, could save lives and reduce pressure on healthcare systems.
Although cancer has many causes and cannot be eliminated through infection control alone, the researchers conclude that a substantial proportion of cases may be preventable through coordinated public-health action. Better vaccination coverage, earlier diagnosis and timely treatment could therefore play a major role in reducing cancer incidence worldwide.
