A 2.3M-Case Analysis Found This Unexpected Cancer Risk Factor
An HPV vaccine can feel like protection against an infection. A hepatitis B shot can feel like another routine vaccine.
And a screening test might just seem like one more appointment to check off your list. But these forms of preventive care can also help lower your risk of certain cancers.
In a recent analysis1, researchers looked at how much of the world's cancer burden could be linked to infections. The findings highlight an often-overlooked part of cancer prevention.
About the analysis
Researchers used global cancer data to estimate how many new cancer cases in 2024 could be attributed to 12 infectious agents known to cause cancer in humans. The analysis included bacteria, viruses, and parasites and examined differences by country, sex, age, and region.
Importantly, this doesn't mean an infection directly caused every individual cancer case in the analysis.
Researchers estimated the proportion of cancer cases in the population that could be attributed to these infections based on established evidence linking them to cancer.
2.3 million cancer cases were linked to infections
The analysis estimated that 2.3 million new cancer cases worldwide in 2024 were attributable to infections. That's about 12% of all new cancer cases, or roughly 1 in 8.
Five infections accounted for most of this burden.
H. pylori was linked to the largest number of cases, primarily stomach cancer. HPV followed, associated with nearly all cervical cancer cases as well as some cancers of the anus, penis, and throat.
Hepatitis B and C viruses were mainly linked to liver cancer, while Epstein-Barr virus (EBV) contributed primarily to nasopharyngeal cancer.
The burden varied by region, too. Eastern Asia had the largest share of infection-attributable cancer cases, while low- and middle-income countries accounted for most cases globally.
About three-quarters of these cases occurred in low- and middle-income countries.
Why an infection can become a cancer risk
An infection doesn't automatically lead to cancer. The bigger concern is what can happen when certain infections persist for years.
For example, long-term H. pylori infection can cause ongoing inflammation in the stomach and gradually contribute to changes that raise cancer risk. HPV, HBV, and HCV can similarly cause lasting changes or inflammation in infected tissues.
That's where prevention comes in. Some of these infections can be prevented through vaccination, while others can be detected early through testing and, in some cases, treated.
Addressing an infection earlier can create an opportunity to reduce its long-term consequences.
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A few ways to lower your risk
You don't need to completely change your health routine. A few familiar preventive-care steps can help:
- Check your vaccine status: HPV and hepatitis B vaccines can prevent infections associated with several cancers. If you're unsure whether you're vaccinated or need another dose, ask a health professional.
- Stay current with screening: Cervical cancer screening can detect HPV-related changes before they develop into cancer. Depending on your health history and risk factors, testing for H. pylori, HBV, or HCV may also be appropriate.
- Ask about testing: If you have risk factors for one of these infections or aren't sure whether you've been tested, bring it up at your next appointment. Some infections can be treated or managed, potentially reducing their long-term health consequences.
The takeaway
Some cancer prevention starts long before cancer is on the radar. Vaccination, screening, and timely treatment can help reduce the impact of several infections tied to millions of cases worldwide.
