These infections are behind 1 in 8 cancer cases worldwide, study finds - USA Today
Millions of cancer cases worldwide, about 1 in 8, have an underlying cause that is not only treatable but preventable altogether, according to a new study.
The answer lies in infections, according to research published this month in The Lancet Oncology, including two of the most common infections in the United States. Roughly 12% of new cancer cases reported globally in 2024 could be traced back to just 12 infections, the authors found, meaning roughly 2.3 million cancer illnesses worldwide could potentially have been prevented.
Five of those infections accounted for more than 2.2 million of the estimated 2.3 million infection-attributable cancer cases recorded in the study, and two โ the common stomach infection H. pylori and the sexually transmitted HPV โwere behind about 1.5 million.
The good news? According to the researchers, we already know how to stop and treat these infections. The bad news? In some countries, that's not happening.
Other infections identified as being linked to cancer included HIV, Kaposi's sarcoma-associated herpesvirus, Schistosoma haematobium (a blood parasite common in Africa and the Middle East), Human T-cell lymphotropic virus type 1, Opisthorchis viverrini (a liver parasite found in Southeast Asia), Clonorchis sinensis (another liver parasite from Southeast Asia) and Merkel cell polyomavirus (a virus known primarily for causing cancer, called an oncovirus).
The study doesn't track every individual cancer case. Instead, it uses global cancer data and previous research to estimate how many cancers are linked to infections. The authors say the figures are the best available estimates, but gaps in cancer reporting in some parts of the world mean the totals aren't exact. Plus, it only counts infections already known to have some association with cancer - there could be others that don't yet have enough evidence to connect the two.
Cancer registries are less complete in some regions, particularly in lower-income countries, making it difficult to measure the true global burden of infection-related cancers. This is of particular note for this study, as it found that 77% of infection-related cancer cases occurred in low- and middle-income countries. Eastern Asia, Sub-Saharan Africa and Southeast Asia were among the regions with the largest cancer burden.
It's important to remember that while 12% of all global cancer cases is a significant number, most cancers are not caused by infection, at least not according to what scientists know right now.
While infection may not be the primary driver of cancer behind all cancers nationwide, it accounts for a disproportionate number of cases within certain types of cancers, such as cervical cancer. The study found that the vast majority of cervical cancer cases can be attributed to HPV, for example.
Researchers also noted that this means several cancers could be prevented with tools we already have but aren't being used. In these cases, infection control, which is already a well-established science, could lead to cancer control.
While the authors noted that more research is needed, especially for some infection-cancer relationships still being explored, like Epstein-Barr, we already have proven methods of addressing certain risks. Areas with the highest cancer burden do not have as ready access to the resources used to track, prevent and control infection, they found.
