Up to four in ten cancer cases worldwide could be prevented, according to a new global analysis by the World Health Organization (WHO) and its International Agency for Research on Cancer (IARC). The study, published to mark World Cancer Day on Wednesday, examines 30 preventable causes of cancer, including tobacco, alcohol, high body mass index, physical inactivity, air pollution, ultraviolet radiation, and – for the first time – nine cancer-causing infections.
The analysis estimates that 37% of all new cancer cases in 2022, roughly 7.1 million cases, were linked to preventable causes, highlighting the enormous potential of prevention in reducing the global cancer burden. Drawing on data from 185 countries and 36 cancer types, the study identifies tobacco as the leading preventable cause, accounting for 15% of all new cancer cases globally, followed by infections at 10% and alcohol consumption at 3%.
Three cancer types – lung, stomach, and cervical cancer – accounted for nearly half of all preventable cases in both men and women. Lung cancer was primarily linked to smoking and air pollution; stomach cancer was largely attributable to Helicobacter pylori infection; and cervical cancer was overwhelmingly caused by human papillomavirus (HPV).
“This is the first global analysis to show how much cancer risk comes from causes we can prevent,” said Dr André Ilbawi, WHO Team Lead for Cancer Control and author of the study. “By examining patterns across countries and population groups, we can provide governments and individuals with more specific information to help prevent many cancer cases before they start.”
The burden of preventable cancer was substantially higher in men than in women, with 45% of new cases in men compared with 30% in women. In men, smoking accounted for 23% of new cases, followed by infections at 9% and alcohol at 4%. Among women, infections caused 11% of new cases, followed by smoking at 6% and high body mass index at 3%.
“This landmark study is a comprehensive assessment of preventable cancer worldwide, incorporating for the first time infectious causes alongside behavioural, environmental, and occupational risks,” said Dr Isabelle Soerjomataram, Deputy Head of the IARC Cancer Surveillance Unit and senior author of the study. “Addressing these preventable causes represents one of the most powerful opportunities to reduce the global cancer burden.”
Preventable cancers varied widely between regions. Among women, rates ranged from 24% in North Africa and West Asia to 38% in sub-Saharan Africa. Among men, the highest burden was observed in East Asia at 57%, and the lowest in Latin America and the Caribbean at 28%. These differences reflect variations in exposure to risk factors, as well as socioeconomic development, national prevention policies, and health system capacity.
The findings underscore the need for context-specific prevention strategies, including strong tobacco control measures, alcohol regulation, vaccination against cancer-causing infections such as HPV and hepatitis B, improved air quality, safer workplaces, and healthier food and physical activity environments. WHO experts call for coordinated action across sectors, from health and education to energy, transport, and labour, to prevent millions of families from experiencing the burden of a cancer diagnosis.
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