Vaping is likely to cause lung and oral cancer, according to a comprehensive new review of evidence by Australian researchers, who have identified early warning signs in the body strongly linked to cancer risk. The study, led by the University of New South Wales in Sydney, analysed reviews of evidence from animal studies, human case reports, and laboratory research published between 2017 and 2025, making it one of the most detailed assessments to date on whether nicotine e-cigarettes could cause cancer.
Early Warning Signs and Pre-Carcinogenic Changes
The review, published in the journal Carcinogenesis, found that vaping is associated with pre-carcinogenic changes, including DNA damage and inflammation. Co-author Adjunct Professor Bernard Stewart emphasized, "There is no doubt that the cells and tissues of the oral cavity, the mouth and the lungs are altered by inhalation from e-cigarettes." These biological changes are known to lead to cancer, though the exact level of risk remains uncertain due to a lack of long-term data.
Challenges in Measuring Risk
Because modern e-cigarettes were only invented in the early 2000s, there is insufficient long-term data from large populations to determine definitive cancer risk. Many vapers also smoke, complicating efforts to isolate the effects of vaping alone. The review did not measure how many people might develop cancer from vaping but assessed whether it causes biological changes that lead to the disease.
However, the study included case reports from dentists who observed oral cancer in individuals who had only vaped and never smoked. Animal studies also showed that mice exposed to e-cigarette vapour developed lung tumours at higher rates than unexposed mice, though such findings may not directly translate to humans.
Urgent Call for Regulatory Action
Lead author Associate Professor Freddy Sitas warned against repeating the mistakes made with smoking, which took decades to be recognized as a cause of lung cancer. He stated, "We risk repeating that same fate with vaping if we don’t take emerging research and warning signs seriously." The researchers urged regulators to act now to protect people, especially children, from harm, rather than waiting for conclusive evidence that could take years or decades.
Calvin Cochran, a research fellow at the University of Otago in New Zealand, supported this view, noting that nearly 8,000 studies were assessed to reach the conclusion. He emphasized, "Every study like this should be considered seriously by policymakers, governments, and health organizations."
Debate on Safety Compared to Smoking
While some experts caution against overinterpreting the findings, such as Professor Stephen Duffy from Queen Mary University London, who said vaping does not involve the combustion products with massive carcinogenic effects found in smoking, Stewart argued it is crucial to assess vaping's cancer risk "in their own right." Professor Becky Freeman from the University of Sydney added, "This study is the first to assert that there is likely an increased cancer risk for people who vape, compared to people who do not vape," highlighting the importance for young non-smokers.
The researchers concluded that vaping is not a safe alternative to smoking and called for stricter regulations, such as limiting access to pharmacies for those using vapes to quit smoking, to balance harm reduction and prevention.
