A major new global analysis suggests that almost seven million cancer cases each year could be prevented through measures such as vaccination, reduced tobacco use, improved diet, and cleaner air. The World Health Organization (WHO) researchers behind the study say the findings reveal a “powerful opportunity” to reduce the burden of cancer worldwide.
The report, produced by WHO scientists and published in the journal Nature Medicine, estimates that around 37% of all cancers are linked to factors that can be avoided. These include infections, lifestyle choices, and environmental pollutants—many of which can be addressed through public health action and individual behaviour change.
Preventable Causes Include Infection, Smoking and Pollution
Among the cancers that could be prevented are those caused by human papillomavirus (HPV), which can lead to cervical cancer and is largely avoidable through vaccination. Tobacco smoking remains one of the leading causes of cancer globally, contributing to many tumours across the body.
The researchers analysed 30 known risk factors that increase cancer risk, including:
- Tobacco use, which directly causes DNA damage
- Ultraviolet (UV) radiation, a major cause of skin cancer
- Obesity and physical inactivity, which alter hormones and inflammation
- Air pollution, which may activate dormant cancer cells
The analysis also included nine infectious agents known to cause cancer, such as HPV, hepatitis viruses (linked to liver cancer), and Helicobacter pylori, a bacterium associated with stomach cancer.
Global Data Highlights the Main Drivers
The team used cancer data from 2022 and compared it with exposure data from a decade earlier, covering 185 countries. Their statistical modelling found that the three biggest preventable causes of cancer were:
- Smoking – responsible for about 3.3 million cases
- Infections – responsible for about 2.3 million cases
- Alcohol use – responsible for about 700,000 cases
However, the study also highlights how cancer risk varies widely across regions and between men and women. In general, 45% of cancers in men were considered preventable, compared with 30% in women—a difference partly driven by higher smoking rates among men.
Regional Differences Shape Prevention Needs
The study shows that prevention strategies must be tailored to local realities:
- In Europe, the leading preventable causes of cancer among women are smoking, infections, and obesity.
- In sub-Saharan Africa, infections dominate, accounting for nearly 80% of preventable cancer cases in women.
This regional variation underscores the need for targeted policies and interventions rather than a one-size-fits-all approach.
The Most Preventable Cancers
According to the report, lung cancer (linked to smoking and air pollution), stomach cancer (linked to H. pylori infection), and cervical cancer (linked to HPV infection) together account for almost half of all preventable cancers.
Dr Isabelle Soerjomataram, deputy head of the IARC Cancer Surveillance Unit, said many people may be surprised by the high proportion of cancers that are preventable. She described the finding as “a substantial number” and a major public health opportunity.
A “Powerful Opportunity” for Public Health
Dr André Ilbawi, WHO’s team lead for cancer control, called the study “good news,” arguing that it shows cancer is not always inevitable and that effective policies can make a real difference. He highlighted the success of countries that have implemented strong tobacco controls or HPV vaccination programmes.
“The percentage of preventable cancers can change over time,” Dr Ilbawi said, “and our goal is to push it as close to zero as possible.”