LYON, France — About one in eight new cancer cases worldwide — an estimated 2.3 million cases in 2024 — can be attributed to infections, according to a major study by the International Agency for Research on Cancer published Monday in The Lancet Oncology.
The study, by the World Health Organization’s specialized cancer research agency, analyzed 12 infectious agents known to cause cancer. Five pathogens accounted for nearly all infection-related cases: Helicobacter pylori, responsible for about 760,000 cases, mostly stomach cancer; HPV, about 750,000, mostly cervical cancer; hepatitis B, about 360,000 liver-cancer cases; the Epstein-Barr virus, about 260,000 cases including nasopharyngeal cancers and lymphomas; and hepatitis C, about 160,000 liver-cancer cases.
The infections were linked to more than 20 cancer types, including stomach, liver, blood and cervical cancers, according to the researchers. The burden falls hardest on poorer nations: about 77 percent of infection-related cancers occurred in low- and middle-income countries, with Eastern Asia carrying the heaviest load at roughly 990,000 cases.
Many of these cancers are preventable, the study’s authors said. HPV and hepatitis B vaccination, cervical-cancer screening and antiviral treatments all reduce risk. There is no vaccine for hepatitis C, but antiviral drugs cure most infections.
“Vaccination, screening and treatment have helped,” said IARC scientist Dr. Harriet Rumgay, “but infection-related cancers still hit low- and middle-income countries hardest.”
The researchers noted that an apparent decline from an 18-percent peak in 2002 cannot be confidently compared with today’s figures because of changes in data sources and methods.
