Nicotine e-cigarettes are likely carcinogenic to humans and may be linked to lung and oral cancers. This is the conclusion reached by the authors of a qualitative risk assessment published in the journal Carcinogenesis and based on an analysis of studies from 2017 to 2025.
The authors of the review emphasize that there is currently insufficient long-term population data on actual incidence rates, as vaping has emerged relatively recently. Therefore, the researchers relied on a body of other evidence—biomarkers of harm in humans, animal experiments, the chemical composition of aerosols, and mechanisms related to carcinogenesis.
The review states that changes considered to be precancerous markers have already been observed in vape users, including DNA damage, oxidative stress, inflammation, and epigenetic changes in the tissues of the respiratory tract and oral cavity. Additionally, in experiments on mice, exposure to e-cigarette aerosols was linked to the development of lung tumors.
The researchers specifically note that their conclusion pertains specifically to nicotine vapes and is phrased as “likely to be carcinogenic,” meaning probable carcinogenicity rather than a definitively quantified risk. The authors also write that it is currently impossible to accurately estimate the future burden of cancer cases associated with vaping.
The publication increases pressure on regulators and the market, as it calls into question the notion of vaping as a “safe alternative” to smoking. At the same time, some external experts urge caution in interpreting the findings, noting that vaping does not involve the combustion of tobacco and that longer-term human studies are still needed for definitive assessments.
