A new review led by UNSW Sydney reports that nicotine-based e-cigarettes are likely to contribute to cancers of the lung and oral cavity. Published in Carcinogenesis, the paper synthesizes international evidence from clinical monitoring, animal studies and laboratory research, and includes specialists in pharmacy, epidemiology, thoracic surgery and public health.
The authors say vaping has often been assessed as a route into cigarette smoking, but less research has focused on whether e-cigarettes may cause cancer independently. They cite multiple findings pointing in that direction: carcinogenic chemicals in aerosols, including volatile organic compounds and metals from heating coils; biomarkers associated with DNA damage, oxidative stress and inflammation; mouse studies showing lung tumors; and cell experiments indicating disruptions in cancer-related biological processes.
Prof. Stewart, one of the review’s authors, describes the evidence as consistent across disciplines, while noting that the review does not estimate the number of cancer cases attributable to vaping. The researchers say precise risk estimates will require longer-term population studies, because e-cigarettes have been widely available for only about two decades.
The review also discusses public health concerns in Australia, where vaping products became available around 2008 and grew popular among younger users, often through flavored and brightly packaged products. Regulations introduced in 2023 restrict disposable and non-therapeutic vapes, while therapeutic products are limited to pharmacy sale for smoking cessation.
Co-author Associate Professor Freddy Sitas says many smokers who try vaping continue to smoke cigarettes, a pattern known as dual use. The researchers cite recent U.S. epidemiological evidence associating combined smoking and vaping with higher lung cancer risk than smoking alone.
The authors compare current uncertainty around vaping with the long history of establishing smoking as a cause of lung cancer. They argue that ongoing studies are needed, but that existing evidence warrants attention from scientists, regulators and clinicians alike.