Millions of Cancer Cases Linked to Infections Worldwide, Study Finds

An estimated 2.3 million cancer cases worldwide in 2024 were linked to infections, accounting for roughly one in eight new cancer diagnoses, according to a new analysis from the International Agency for Research on Cancer (IARC).

According to Fox News, researchers identified 12 infections associated with cancer in humans, including human papillomavirus (HPV), Helicobacter pylori (H. pylori), hepatitis B and C viruses, Epstein-Barr virus, HIV, and several other viruses and parasites.

Five of those infections were responsible for nearly all of the infection-related cancer cases recorded globally, according to the study, which was led by researchers in France using 2024 global cancer data. The findings were published in The Lancet Oncology on Sept. 28.

Dr. Harriet Rumgay, a scientist in IARC's Cancer Surveillance Branch and a co-author of the study, said infection prevention could play a significant role in reducing cancer rates worldwide.

"Despite progress in vaccination and screening, infection-related cancers remain a major global challenge," Rumgay said in a press release, noting that the burden falls disproportionately on low- and middle-income populations.

Researchers said many cancers associated with infections could potentially be prevented through vaccination, screening or treatment of the infections themselves.

Dr. Joshua Cohen, medical director of the Gynecologic Cancer Program at City of Hope Orange County in Irvine, California, who was not involved in the research, stressed that most cancers are not caused by infections.

"We know that there are certain infections that we are exposed to over our lifetime that may result in an increased risk of certain cancers," Cohen told Fox News Digital.

HPV is associated with cancers of the cervix, vagina, anus, penis and oropharynx, or the back of the throat. Cohen said about 80% of people have been exposed to certain HPV strains, though the body's immune system clears the infection in most cases.

H. pylori is another common infection associated with cancer, particularly gastric cancer. Cohen said it is more prevalent in some parts of the world, including Southeast Asia, and advised people with peptic ulcer disease or significant upper abdominal pain to discuss testing with a gastroenterologist.

The study's authors acknowledged limitations, including reliance on population-level cancer estimates and differences in the quality of available data between countries. The analysis also focused only on infections already established as cancer-causing, meaning its estimates may not capture every possible infection-related cancer case.

Cohen emphasized that having an infection linked to cancer does not mean a person will develop the disease. He pointed to HPV vaccination, appropriate testing and treatment as steps that can reduce cancer risks associated with certain infections.

Symptoms including persistent upper abdominal discomfort, acid reflux, abnormal vaginal bleeding or pain with swallowing can have many causes, but Cohen said people experiencing them should discuss the symptoms with a medical professional.