EuroWire, LYON: Nearly four in 10 cancer cases worldwide could be prevented by reducing exposure to known, modifiable risk factors, according to a new analysis from the World Health Organization and its cancer research agency released for World Cancer Day. The assessment estimated that 37% of new cancer diagnoses in 2022, about 7.1 million of 18.7 million cases, were linked to risks that can be reduced through public health measures and individual prevention.
The study, led by the International Agency for Research on Cancer, analyzed 185 countries and looked across 36 cancer types. Researchers assessed 30 preventable causes spanning behavioral risks, infections, environmental exposures and occupational hazards, using global data to estimate the share of cancers attributable to each factor. The findings were published in the journal Nature Medicine and presented as a global snapshot of how many cancers could be avoided by addressing established carcinogenic exposures.
Tobacco use was the largest single contributor, accounting for 15% of all new cancer cases worldwide in 2022, the report said. Infections were the second largest category at 10%, reflecting the role of pathogens such as high risk human papillomavirus, hepatitis B and C viruses, and Helicobacter pylori, which are linked to cervical, liver and stomach cancers. Alcohol use accounted for 3% of new cancer cases globally, the analysis found, with other factors including excess body weight, diet, and air pollution contributing smaller shares.
Nearly half of preventable cancers were concentrated in three diseases: lung, stomach and cervical cancer, the report said. Lung cancer was tied mainly to tobacco use and air pollution, while stomach cancer was strongly linked to H. pylori infection. Cervical cancer was primarily linked to HPV infection, which is preventable through vaccination and screening programs. The concentration of preventable cases in these cancers highlights how targeted measures can reduce overall cancer burden, the authors said.
Leading preventable drivers
Preventable risk factors affected men and women differently, the study found. An estimated 45% of new cancer cases in men were linked to modifiable causes, compared with about 30% in women. Among men, smoking alone accounted for roughly 23% of new cancer cases, followed by infections at 9% and alcohol at 4%. Among women, infections were the largest contributor at 11%, with smoking at 6% and high body mass index at 3%, reflecting differences in exposure patterns and cancer types.
The analysis also showed wide regional variation. For women, the share of preventable cancers ranged from 24% in North Africa and West Asia to 38% in sub-Saharan Africa, where infection related cancers remain a major driver. For men, the highest share was estimated in East Asia at 57%, while Latin America and the Caribbean had the lowest estimated share at 28%. The report said regional patterns reflect differences in tobacco use, vaccination and screening coverage, infection prevalence, air quality and occupational exposures.
Vaccines, regulation, and exposure controls
The researchers said prevention policies can reduce cancer risk at population scale by focusing on the largest drivers. Measures cited included stronger tobacco control, such as higher taxes and smoke free policies, and steps to curb harmful alcohol use through regulation and public health interventions. Expanding vaccination against HPV and hepatitis B, improving access to cervical screening, and treating infections such as H. pylori were also highlighted as strategies that can reduce future cancer cases.
The report also pointed to actions beyond the health sector, including improving outdoor air quality and limiting exposure to carcinogens at work. It assessed 13 occupational exposures and linked cancer risk to substances and agents such as asbestos, silica, benzene, diesel engine exhaust, formaldehyde, chromium and nickel. The authors said reducing workplace exposure, enforcing safety standards and improving monitoring can cut risk, particularly in industries where carcinogenic hazards remain common.
The authors cautioned that estimates depend on the quality and availability of exposure and cancer incidence data, which can be uneven across countries. They also said some risk factors could not be included because comparable global data are not available, meaning the preventable share could be underestimated. Even with those limits, the analysis concluded that a substantial portion of the global cancer burden is connected to known, avoidable risks and can be reduced through prevention programs and policy action.