Nearly four out of ten new cancer diagnoses around the world could have been avoided, according to a major new analysis that examined dozens of cancer types across almost 200 countries.
The research suggests that in 2022 alone, about seven million cancer cases were connected to risk factors that people can modify, manage, or reduce through lifestyle changes, medical interventions, or public health measures. Among these, tobacco smoking emerged as the single most significant contributor to global cancer cases, followed by infectious diseases and alcohol consumption. The authors argue that reducing exposure to these risks represents one of the most effective ways to lower the future global cancer burden.
The findings were published in Nature Medicine.
Cancer remains one of the leading causes of death worldwide, and its incidence is projected to keep rising if current patterns persist. Earlier studies have estimated that roughly 44 percent of global cancer deaths are linked to preventable causes. However, most previous research focused primarily on deaths rather than new diagnoses, and often examined only one risk factor at a time.
To provide a broader picture, the research team analyzed cancer case data from 2022 covering 36 different cancer types in 185 countries. They included 30 well-established, modifiable risk factors, such as smoking, alcohol use, and certain infections.
The researchers combined this with exposure data from 2012, which reflected how widely people were exposed to these risks. They then calculated how many cancer cases could be directly attributed to each factor.
In 2022, there were 18.7 million new cancer cases worldwide. Of these, about 7.1 million — roughly 38 percent — were linked to avoidable causes. Smoking alone accounted for about 15 percent of preventable cases, while infections contributed around 10 percent and alcohol about 3 percent. Lung, stomach, and cervical cancers together made up nearly half of all preventable cancer diagnoses.
Among women, about 30 percent of the 9.2 million new cancer cases could have been prevented. More than 11 percent were associated with infections, particularly human papillomavirus, the main cause of cervical cancer. Most of these cases occurred in low- and middle-income regions, especially sub-Saharan Africa, where cervical cancer rates remain alarmingly high. In contrast, smoking was the primary cancer risk factor for women in wealthier regions such as North America and much of Europe.
For men, smoking was by far the dominant risk factor, responsible for nearly one-quarter of the 4.3 million preventable cancer cases worldwide. This pattern held true in both high- and low-income countries. Infections ranked second, particularly in parts of Africa, Asia, and South America, followed by alcohol consumption.
Experts outside the study have praised the research for its depth and global scope. One epidemiologist described it as a strong and valuable contribution that highlights the urgent need for more aggressive cancer prevention strategies. The comprehensive data, he noted, will allow for more accurate comparisons across regions.
The lead researcher hopes the results will guide policymakers in designing targeted prevention programs based on the most significant risk factors in different parts of the world. She emphasized that effective cancer prevention must be tailored to local conditions rather than relying on a universal approach.
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