Review finds nicotine vapes likely raise lung and oral cancer risk
UNSW-led researchers say evidence from human biomarkers, animal work and lab studies points to cancer risks from nicotine e-cigarettes.
By Priya Raghavan · Science Reporter
3 min read
An international review led by UNSW Sydney has concluded that nicotine e-cigarettes are likely to cause cancers of the lung and oral cavity. The finding matters because vaping has often been promoted as a lower-risk alternative to smoking, while the review says evidence of direct cancer risk is now strong enough to warrant attention.
The review, published in Carcinogenesis, assessed research from clinical monitoring, animal experiments and laboratory studies, according to the University of New South Wales. The team included researchers from UNSW, The University of Queensland, Flinders University, The University of Sydney, Royal North Shore Hospital, The Prince Charles Hospital and Sunshine Coast University Hospital.
UNSW said the authors examined carcinogenicity, meaning whether e-cigarettes can contribute to cancer development. The researchers focused on whether vaping may cause cancer independently of conventional tobacco smoking, rather than only through its role in leading some users to cigarettes.
Evidence from several fields
According to UNSW, the review identified cancer-causing substances in e-cigarette aerosols, including volatile organic compounds and metals released from heating coils. It also considered human biomarkers linked to DNA damage, oxidative stress and tissue inflammation.
The authors also reviewed mouse studies that produced lung tumors and laboratory research showing cellular damage and disruptions in biological processes tied to cancer development, UNSW said. Professor Bernard Stewart, one of the study authors, said the combined findings support the conclusion that e-cigarettes are likely to cause lung and oral cancers.
The researchers did not calculate how many cancer cases may be attributable to vaping. Stewart said the assessment was qualitative, and that precise risk estimates will require longer-term studies.
UNSW said e-cigarettes entered the market in the early 2000s and became available in Australia around 2008. They were initially marketed as a potentially safer option than cigarettes and as a way to help smokers quit.
Concerns over dual use
The review also pointed to concern over people who both smoke and vape. Co-author Associate Professor Freddy Sitas of UNSW said many people who try to use e-cigarettes to quit smoking continue using both products.
Sitas and Stewart discussed related evidence in a separate commentary in Cancer Epidemiology. According to UNSW, that commentary cited recent U.S. epidemiological evidence indicating that people who both vape and smoke have an additional four-fold increased risk of developing lung cancer.
The authors also compared the current debate over vaping to the long history of research on cigarettes. UNSW said the commentary notes that decades passed between early warnings about smoking-related disease and the 1964 U.S. Surgeon General’s report identifying smoking as a cause of lung cancer.
Australia tightened vaping rules in 2023, UNSW said. The current rules prohibit disposable and non-therapeutic vapes, while therapeutic vaping products may be sold only through pharmacies for smoking cessation.
The researchers said longer-term population studies will be needed to measure cancer risk more precisely. Their conclusion, according to UNSW, is that the available evidence already points in the same direction across human, animal and laboratory research.
This story draws on original reporting from ScienceDaily.