Infections were linked to an estimated 2.3 million new cancer cases worldwide in 2024, accounting for about 12 per cent of all newly diagnosed cancers, according to a study published in The Lancet Oncology.
The study, titled Global Burden of Cancer Attributable to Infections in 2024: A Worldwide Incidence Analysis, provides an updated assessment of cancers associated with infectious agents.
Researchers from the International Agency for Research on Cancer (IARC) led the study, using data from the Global Cancer Observatory’s GLOBOCAN 2024 database.
The researchers examined cancers attributable to 12 infectious agents classified as Group 1 carcinogens by the IARC Monographs Programme. They estimated the population-attributable fractions, number of cases and age-standardised incidence rates according to sex, age and country.
Helicobacter pylori (H. pylori) was associated with the largest number of infection-related cancer cases, accounting for about 760,000 cases globally.
Human papillomavirus (HPV) followed with approximately 750,000 cases, while hepatitis B virus (HBV) was linked to about 360,000 cases.
Epstein-Barr virus (EBV) accounted for an estimated 260,000 cases, while hepatitis C virus (HCV) was associated with approximately 160,000 cases.
Together, the five infections accounted for most of the cancer cases attributed to infectious agents in the analysis.
The researchers said the findings highlighted the importance of preventing, detecting and treating infections as part of global cancer-control efforts.
They identified several interventions that could help reduce the burden, including HPV and HBV vaccination, testing and treatment for HIV, H. pylori, HBV and HCV, and safer injection practices.
Other preventive measures include condom use and pre-exposure prophylaxis to reduce HIV transmission, as well as screening for precancerous lesions associated with HPV-related cervical and anal cancers.
Eastern Asia recorded the highest absolute number of infection-attributable cancer cases, with about 990,000 cases, representing 42 per cent of the global total.
However, sub-Saharan Africa recorded a higher age-standardised incidence rate than the global average, at 28.5 cases per 100,000 people compared with 22.7 cases per 100,000 globally.
Central and eastern Europe recorded 24.3 cases per 100,000 people, while southeastern Asia recorded 23.1 cases per 100,000.
The researchers said the analysis incorporated newly established links between infections and cancer, as well as additional infectious agents such as HIV and Merkel cell polyomavirus.
It also included additional cancers associated with previously established carcinogenic infections, including the recently established association between EBV and gastric cancer.
A separate analysis of EBV-associated cancers found significant regional differences in the types of cancer linked to the virus.
The researchers said the findings could help guide research and development investments in new cancer prevention tools, particularly interventions targeting EBV.
They also stressed the need to strengthen vaccination, screening, diagnosis and treatment programmes to reduce the global burden of cancers associated with infectious agents.
The study concluded that infectious agents remain an important preventable cause of cancer worldwide, making effective infection control a key component of broader cancer-prevention strategies.
