Review links nicotine e-cigarettes to lung and oral cancer

Nicotine vaping was long marketed as a cleaner swap for cigarettes, especially for smokers trying to quit. A new UNSW Sydney-led review pushes back hard on that assumption, concluding that nicotine-based e-cigarettes are likely to cause lung cancer and oral cancer and that health authorities should not wait for decades of perfect proof before acting.

The review, published in Carcinogenesis on 31 March 2026 and led by Adjunct Professor Bernard Stewart AM with co-author Adjunct Associate Professor Freddy Sitas, pulled together peer-reviewed research from 2017 to 2025. UNSW said the authors summarized more than 100 studies and drew on thousands more, combining clinical research, animal experiments and laboratory investigations of chemicals generated by e-cigarettes. The paper’s central finding was blunt: “Considering all the findings ... e-cigarettes are likely to cause lung cancer and oral cancer.”

The researchers used an early carcinogenicity framework developed by the World Health Organization and the International Agency for Research on Cancer, assessing evidence across biomarker studies, case reports, rodent bioassays and mechanistic data. UNSW said all ten key characteristic criteria were fulfilled, though the review remained qualitative and did not assign a numeric risk estimate. The breadth of the evidence mattered: the conclusion was not drawn from one study, but from a pattern that held across human, animal and lab data.

That warning lands in a policy environment that has already shifted, at least in Australia. UNSW said e-cigarettes first appeared in the early 2000s and reached Australia around 2008, marketed as a “safer” alternative to tobacco and a possible quitting aid. But the federal government tightened the rules in 2023 and, in 2024, limited all vapes and vaping products to pharmacy sales for smoking cessation or nicotine dependence. Tobacconists, vape shops and convenience stores can no longer legally sell them.

The review also used history to make its case. UNSW noted that it took about 100 years of research to confirm that smoking causes lung cancer in 1964, and another 50 years to calculate the full hazard of tobacco smoking. The authors argued that waiting for the same kind of complete epidemiological certainty on vaping could leave public health agencies behind the curve.

A U.S. study cited by UNSW added to that concern. In that cohort, only 3% of people who used e-cigarettes to quit smoking fully replaced tobacco, while dual use was linked to lung cancer risk rising from about 13-fold for tobacco smoking to 38-fold. ABC News reported that experts now want tougher enforcement against incorrectly labeled and black-market vapes, and said vaping can no longer be described as safer than smoking.

The broader message is clear: the evidence has advanced enough to change the conversation now, especially for young people drawn to flavored devices. As the review frames it, the health risks are no longer a distant possibility but an emerging public-health problem demanding faster regulation, sharper warnings and less faith in the idea that nicotine vaping is harmless.