2.3 million cancers in 2024 were caused by infections, one in eight of all cases
An IARC worldwide incidence analysis puts the infection-attributable share at 12%, led by H pylori and HPV, with eastern Asia carrying the heaviest load and most of the toll preventable.
| Group | Value (new cancer cases) |
|---|---|
| H pylori | 760000 |
| HPV | 750000 |
| Hepatitis B | 360000 |
| Epstein-Barr virus | 260000 |
| Hepatitis C | 160000 |
A worldwide incidence analysis from the International Agency for Research on Cancer (IARC), published in The Lancet Oncology on 28 September, puts a current figure on one of the most preventable fractions of the cancer burden: the share caused by chronic infections. Using the Global Cancer Observatory's GLOBOCAN database of cancer incidence in 2024, the authors estimate attributable fractions, absolute case counts, and age-standardised incidence rates for cancers linked to 12 infectious agents classified as Group 1 carcinogens by the IARC Monographs programme [s1].
What the numbers say
The analysis covered 12 infectious agents classified as Group 1 carcinogens: Helicobacter pylori, HPV, hepatitis B and hepatitis C viruses, Epstein-Barr virus, Kaposi's sarcoma-associated herpesvirus, Schistosoma haematobium, human T-cell lymphotropic virus, Opisthorchis viverrini, Clonorchis sinensis, Merkel cell polyomavirus, and HIV [s1]. For each, the authors estimated population-attributable fractions, absolute case numbers, and age-standardised incidence rates, then aggregated the results by United Nations geographical subregion and World Bank income group [s1].
An estimated 2.3 million new cancer cases were attributable to infections globally in 2024, equivalent to 12% of all cancer cases [s1]. The largest single contributor was Helicobacter pylori, the stomach bacterium, at 760,000 cases (population-attributable fraction 4%), followed closely by human papillomavirus, or HPV, at 750,000 cases (4%) [s1]. Hepatitis B virus accounted for 360,000 cases (2%), Epstein-Barr virus for 260,000 (1%), and hepatitis C virus for 160,000 (under 1%) [s1].
The burden is not spread evenly. Eastern Asia carried the heaviest load by far, with 990,000 cases — 42% of the global total — and an age-standardised incidence rate of 31.9 per 100,000 [s1]. That rate sat well above the global average of 22.7 per 100,000 [s1]. Rates were also higher than average in sub-Saharan Africa (28.5), central and eastern Europe (24.3), and southeastern Asia (23.1) [s1]. A focused analysis of Epstein-Barr-virus-attributable cancers showed the mix of cancer types varying from region to region [s1].
How it compares with the last worldwide count
The value of a GLOBOCAN-based analysis is that it can be repeated as the underlying cancer data are refreshed, letting researchers watch the trend rather than a single snapshot. The same group's previous worldwide analysis, for 2018, estimated 2.2 million infection-attributable cancer cases and an age-standardised incidence rate of 25.0 per 100,000 person-years [s2]. In that count the leading causes were H pylori (810,000 cases, rate 8.7 per 100,000), HPV (690,000, 8.0), hepatitis B (360,000, 4.1), and hepatitis C (160,000, 1.7) [s2].
Read side by side, the two analyses tell a measured story. The absolute number of cases has edged up, from 2.2 million in 2018 to 2.3 million in 2024, which is consistent with a growing and ageing world population [s1][s2]. But the age-standardised rate — the measure that strips out those demographic shifts — has fallen, from 25.0 to 22.7 per 100,000 [s1][s2]. The reshuffling among agents is notable too: H pylori-attributable cases eased from 810,000 to 760,000, while HPV-attributable cases rose from 690,000 to 750,000, narrowing the gap between the top two causes [s1][s2]. Comparisons like this come with a caveat: the two analyses draw on different GLOBOCAN vintages and have been refined over time, so small year-to-year movements should be read as broad direction rather than precise change. The robust signal is the contrast between a rising absolute count and a falling age-standardised rate [s1][s2].
Why it matters
The reason this fraction of the cancer burden attracts so much attention is that it is, in large part, avoidable. The authors stress that their findings underline the importance of infection control for cancer prevention, and they list approaches that are scientifically proven but often underused: HPV and hepatitis B vaccination; testing and treatment for HIV, H pylori, hepatitis B, and hepatitis C; safe injection practices; access to condoms and pre-exposure prophylaxis to cut HIV transmission; and screening of precancerous lesions for HPV-driven cervical and anal cancer [s1]. They also argue the numbers strengthen the investment case for new prevention tools, most notably a vaccine against Epstein-Barr virus [s1].
Two framing points help keep the figures in proportion. First, an attributable-fraction estimate is a modelled quantity, not a direct tally of individually confirmed cases: it multiplies cancer incidence by the share of each cancer type linked to a given agent, so its accuracy depends on both the GLOBOCAN incidence data and the attribution assumptions [s1]. Second, the geographic concentration is itself the actionable finding — with eastern Asia and sub-Saharan Africa carrying rates well above the global mean, the same vaccines, tests, and treatments would avert the most cancers where the burden is heaviest [s1]. The 2018 comparison makes the direction encouraging: rates are drifting down even as the raw count climbs with population [s1][s2].
Sources
- [s1] Global burden of cancer attributable to infections in 2024: a worldwide incidence analysis. The Lancet Oncology. https://doi.org/10.1016/S1470-2045(26)00307-4
- [s2] Global burden of cancer attributable to infections in 2018: a worldwide incidence analysis. The Lancet Global Health. https://doi.org/10.1016/S2214-109X(19)30488-7
Sources
- Global burden of cancer attributable to infections in 2024: a worldwide incidence analysis — The Lancet Oncology , September 28, 2026
- Global burden of cancer attributable to infections in 2018: a worldwide incidence analysis — The Lancet Global Health , February 1, 2020
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