80 Quick summary: A global study found that 37.8% of the 18.7 million new cancer cases recorded in 2022 were linked to 30 modifiable risk factors, with smoking, infections, and alcohol as the leading contributors. The burden falls disproportionately on men and varies sharply by region, with infectious agents driving cancer rates in sub-Saharan Africa while smoking and high BMI are more prominent in wealthier countries. The findings make a strong case for targeted prevention policies, including expanded HPV vaccination, stricter tobacco controls, and measures to reduce air pollution, as cost-effective tools for reducing cancer incidence at population level. A major new study has found that over a third of all cancer cases diagnosed globally in 2022 could have been prevented by eliminating exposure to known, modifiable risk factors. The research, published in Nature Medicine, analysed data from 185 countries and identified smoking, infections, and alcohol consumption as the three leading contributors to preventable cancer worldwide. Out of 18.7 million new cancer cases recorded in 2022, an estimated 7.1 million, or 37.8%, were linked to 30 modifiable risk factors. These included tobacco use, high body mass index, physical inactivity, air pollution, ultraviolet radiation, and a range of infectious agents and occupational exposures. The scale of the finding underscores the potential for meaningful reductions in cancer incidence through targeted public health action. Tobacco smoking alone was responsible for 15.1% of all new cancer cases, accounting for more than 3.3 million diagnoses. Infections contributed to 10.2% of cases, while alcohol consumption was linked to around 700,000 new cases, or 3.2% of the global total. Lung, stomach, and cervical cancers together made up nearly half of all preventable cancer cases identified in the analysis. The burden of preventable cancer was significantly higher in men than in women. Among men, 45.4% of new cancers were attributable to modifiable risk factors, compared with 29.7% in women. In men, tobacco and infections dominated, driving high rates of lung, stomach, and liver cancers. Among women, the picture was more varied, with infections, smoking, and high BMI emerging as the principal concerns depending on the region. The research also revealed stark regional differences in the distribution of risk factors. In sub-Saharan Africa, infectious agents drove nearly a third of cancer cases in women, reflecting persistently high rates of cervical cancer linked to human papillomavirus. By contrast, in higher-income regions such as North America and Northern Europe, smoking and high BMI were the more prominent causes. East Asia recorded the highest male cancer burden attributable to modifiable risks, with 57.2% of new male cancer cases in that region considered preventable. Air pollution was found to account for a notable proportion of lung cancer cases, particularly in East Asia and parts of the Middle East. Ultraviolet radiation was identified as the leading preventable cause of cancer in Oceania, especially in Australia, where melanoma incidence is among the highest in the world. Occupational exposures such as asbestos, diesel engine exhaust, and benzene contributed to a smaller but still significant share of the global cancer burden. The researchers applied a ten-year lag between exposure data and cancer diagnosis to reflect the typical delay between contact with a risk factor and the development of disease. This methodological approach, they argue, better captures the long-term relationship between lifestyle or environmental factors and cancer onset than frameworks focused solely on mortality. The findings point to a clear and pressing need for context-specific prevention strategies. Strengthening HPV vaccination programmes in low-income countries, enforcing tobacco control policies, improving air quality, and promoting healthy weight and physical activity are among the most evidence-based routes to reducing the global cancer burden.