Infections Linked to About One Eighth of Global Cancer Cases, Study Finds

A study published in The Lancet Oncology estimates that around 2.3 million new cancer cases in 2024 – about one in eight globally – were linked to infections that can often be prevented or treated. The research, led by epidemiologists Gary Clifford and Harriet Rumgay of the International Agency for Research on Cancer, analyzed data from the Global Cancer Observatory to identify infection-cancer associations.

Helicobacter pylori and human papillomavirus (HPV) together accounted for more than 1.5 million of those cases, primarily gastric and cervical cancers respectively. Other notable contributors included hepatitis B and C viruses, Epstein-Barr virus, and HIV, for which effective vaccines, screening or therapies exist.

"We can intervene before it gets anywhere near cancer," Clifford said, emphasizing the need for political commitment, funding and public awareness to implement prevention programs.

The burden of infection-related cancers is unevenly distributed, with low- and middle-income countries experiencing 77% of cases due to higher infection prevalence and limited access to preventive measures. In the United States, disparities also exist, with certain populations facing higher rates of hepatitis, HPV or H. pylori and reduced vaccination or screening coverage.

Experts not involved in the study noted that while infection increases cancer risk, most infected individuals never develop cancer, and that long-term infection combined with other factors drives malignancy. They stressed that vaccination against HPV and hepatitis B, testing and treatment for H. pylori and hepatitis C, and safe practices such as condom use and sterile injections could substantially lower future cancer incidence.

The authors added that expanding these preventive strategies worldwide could avert hundreds of thousands to millions of cancer cases, underscoring the public health value of infection control in cancer prevention.