Vapes ‘likely to be carcinogenic’: Study

Australian researchers have found e-cigarettes are ‘likely to be carcinogenic’ to humans after a wide-ranging review.
 
The University of New South Wales (UNSW) study, published on Tuesday in the Carcinogenesis journal, looked at peer-reviewed research from 2017–25 to establish whether e-cigarettes are likely to cause cancer in their own right.
 
Looking at the results of clinical studies, as well as animal experiments and laboratory research, the authors concluded nicotine-based e-cigarettes are likely to cause oral and lung cancer.
 
The researchers came from a variety of different disciplines, including pharmacy, epidemiology, thoracic research and public health.
 
Lead author Adjunct Professor Bernard Stewart, a cancer researcher from the UNSW Paediatrics and Child Health discipline, described evidence that vaping caused long-term changes in biomarkers as ‘unequivocal’.
 
‘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,’ he said.
 
‘We’re able to determine that in humans, there is unequivocal pre-carcinogenic change as a consequence of vaping.’
 
When asked about using vapes as a way of stopping smoking, he said nicotine replacement therapy is the ‘established, objective means of intervening in a smoking cessation program above and beyond the commitment of the smoker’.
 
‘But in turn, although e-cigarettes were touted as a means of giving up smoking, physicians generally, oncologists, GPs, the whole medical profession, don’t want to touch them with a barge pole,’ he said.
 
The RACGP’s smoking cessation guidelines include e-cigarettes as a last-line treatment for smokers who have attempted other pharmacotherapy quitting methods that have not worked. 
 
The recommendation, described as ‘conditional’ and made with ‘low certainty’, includes caveats such as the uncertainty around the long-term health effects of vapes, and the fact they are not registered therapeutic goods in Australia.
 
They also say the ‘lack of uniformity’ in vaping devices increases uncertainties, and emphasise that dual use should be avoided and long-term use minimised.
 
Professor Nick Zwar, Chair of the RACGP’s Smoking Cessation Guidelines’ Expert Advisory Group, said while the new research is a ‘really good bit of work’, it is too early to reach a conclusion dismissing vapes as a treatment option.
 
‘I don’t think it changes the message that nicotine vaping is a reasonable therapeutic option when people haven’t succeeded with other methods,’ he told newsGP.
 
‘It’s an argument for prospective studies and continuing research to follow the impact of vaping over time, because I’m sure it’s not going to be completely safe – no one thinks it is.’
 
Professor Stewart, along with epidemiologist and co-author Associate Professor Freddy Sitas, acknowledge that the risk cannot be quantified until much wider cohorts are studied but said their work should be useful for regulators.
 
It follows a rapid rise in vaping over the past decade, particularly among young people.
 
Current regulations ban the sale of nicotine e-cigarettes without a prescription or outside of pharmacies, although these rules are widely flouted via a thriving black market.
 
‘The direction we intend is primarily to influence regulators, to give them further clarity in the need to control what has been described as a youth epidemic,’ Professor Stewart said.
 
Associate Professor Sitas also cited a 2024 study in the Journal of Oncology Research and Therapy  which suggests that smoking and vaping increased the risk of lung cancer fourfold compared to smoking alone.
 
‘It’s one thing to use vapes to reduce tobacco smoking, but a large proportion of that population lands up in dual-use limbo,’ he said.
 
‘Unless there is a proven device to stop people from vaping, then we’re stuck in this high-risk population that starts using both.
 
‘And those people are at much higher risk of getting lung cancer, for example, than just smoking alone.’
 
In an editorial published concurrently in Cancer Epidemiology, Associate Professor Sitas and Professor Stewart call for a precautionary approach while more evidence is established.
 
‘Though smoking was once given the benefit of doubt, the same should not now be accorded to vaping given the strength of relevant carcinogenicity data,’ they wrote.
 
Professor Zwar, however, said dismissing vaping as a last-line treatment for smoking cessation risked ‘throwing the baby out with the bath water’.
 
‘It’s for people who are smoking, that’s what people have got to bear in mind,’ he said.
 
‘We don’t know exactly how safe or unsafe vaping is, and we’ve always had uncertainties about the long-term health effects.
 
‘I don’t think it is yet possible to know to what extent these risks are there for people who use nicotine e-cigarettes maybe for three months to six months to help them stop smoking.’
 
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