Some infections can raise a person’s risk of developing cancer. As reported on MedPage Today, global analysis estimates that about 2.3 million new cancer cases in 2024—roughly 12% of all cases worldwide—were attributable to infections.
The estimate comes from researchers who analyzed cancer data from countries around the world and considered 12 infectious agents classified as cancer-causing by the International Agency for Research on Cancer. The findings point to opportunities for cancer prevention, including vaccination, screening and treatment of infections.
“Population-attributable” estimates describe the share of cases in a population that may be linked to a particular risk factor. They do not mean that an infection caused cancer in every person counted, or that researchers can determine what caused an individual’s cancer.
Which infections accounted for the most cases?
The analysis estimated the following numbers of cancer cases linked to several infections:
- Helicobacter pylori (H. pylori): 760,000 cases, mainly stomach cancers
- Human papillomavirus (HPV): 750,000 cases, mostly cervical cancers
- Hepatitis B virus (HBV): 360,000 cases, including about 330,000 liver cancers
- Epstein-Barr virus (EBV): 260,000 cases, including cancers of the nose and throat region, as well as some blood cancers
- Hepatitis C virus (HCV): 160,000 cases, including about 130,000 liver cancers
- Kaposi’s sarcoma-associated herpesvirus (KSHV): 35,000 cases
These infections can affect the body in different ways. For example, long-term infection with hepatitis B or C can damage the liver, while some types of HPV can cause cell changes that may lead to cervical cancer.
Prevention options exist—but access varies
Several tools can help reduce infections linked to cancer. HPV and hepatitis B vaccines can prevent infections that contribute to certain cancers. Testing and treatment are available for infections such as H. pylori, hepatitis B, hepatitis C and HIV. Cervical screening can also identify changes early, before they develop into cancer.
Other steps, including safer injection practices and condom use, can reduce the spread of some infections. However, prevention and treatment services are not equally available everywhere.
There is currently no widely available vaccine to prevent EBV infection, although researchers are working toward one. The researchers also highlighted the need for improved ways to prevent KSHV, which causes Kaposi’s sarcoma and is a particular concern in parts of sub-Saharan Africa.
The leading causes differ by region
The estimated share of cancers linked to infections varied considerably around the world. Sub-Saharan Africa had the highest estimated proportion, at 25%, followed by northern Africa and southeastern Asia, both at 16%. In eastern Asia, which accounted for the largest number of infection-attributable cases, H. pylori and hepatitis B were major contributors. HPV was the leading infection-related cause in sub-Saharan Africa.
The researchers said prevention efforts need to reflect local patterns of infection and cancer, as well as the availability of vaccination, screening and treatment. “There is no single prevention strategy that will work equally well everywhere,” lead author Harriet Rumgay, Ph.D., said.
The analysis used cancer estimates and registry data to calculate the number and proportion of cases linked to infections. The authors noted that their estimates did not include separate attributable percentages for women and men, so some differences by sex may not have been captured.
The findings, published in The Lancet Oncology, underscore the potential to prevent some cancers by reducing infection and improving access to proven health services. They are estimates across populations, however, and do not predict any one person’s cancer risk.
