Infections cause about one cancer in eight worldwide, led by H pylori and HPV

Design

Worldwide incidence analysis using population-attributable fractions

Population

GLOBOCAN 2024 new cancer cases worldwide

Primary outcome

Cancers attributable to 12 Group 1 infectious carcinogens

Effect

2.3 million cases (12%); H pylori about 760,000, HPV about 750,000

Using GLOBOCAN 2024 incidence data, this Lancet Oncology analysis estimated how many new cancers were attributable to the 12 infectious agents classified as definite carcinogens. The answer was about 2.3 million, or 12% of all cancers.

Helicobacter pylori accounted for about 760,000 cases and HPV about 750,000, followed by hepatitis B (360,000), Epstein–Barr virus (260,000) and hepatitis C (160,000). Eastern Asia carried 42% of the global total. Age-standardised rates were above the global average of 22.7 per 100,000 in eastern Asia, sub-Saharan Africa, central and eastern Europe and southeastern Asia.

These are modelled estimates built on attributable fractions, not direct counts. But the prevention tools are well established: HPV and hepatitis B vaccination, testing and treating H pylori, HBV, HCV and HIV, safe injection practice, and cervical screening. For an oncologist, much of this sits upstream of the clinic — but family members of patients with gastric, cervical or liver cancer are an obvious place to start.

• Offer H pylori testing to first-degree relatives of patients with gastric cancer, where local guidance supports it.
• Check hepatitis B and C status before chemotherapy or immunosuppression; it also identifies family members to test.
• Support HPV vaccination and cervical screening in women attending with other cancers.
• Remember that many infection-related cancers are preventable before they reach the oncology clinic.

Why it matters

One cancer in eight has a cause that vaccination, screening or antimicrobial treatment can address.

Don't overread it

These are modelled estimates, not observed counts of cancers caused by infection.

The statistics, in plain English

A population-attributable fraction estimates the share of cases that would not have occurred without the infection. It depends on assumptions about prevalence and relative risk, so the totals are estimates with uncertainty rather than counts.

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