Researchers Find Strongest Evidence Yet That Vaping Likely Causes Cancer
A comprehensive review of the evidence conducted by Bernard Stewart and his colleagues has concluded that vaping is likely to cause oral and lung cancers. This study, published recently, marks a significant shift in understanding the health risks associated with electronic cigarettes.
Historical Context and Current Findings
As early as the 1880s, evidence emerged that smoking tobacco damaged lungs, but it took nearly a century to definitively prove it causes lung cancer. Similarly, research on vaping has primarily focused on its role as a gateway to smoking, with uncertainty about its direct cancer-causing potential due to a lack of long-term studies. However, this new review, which analyzed peer-reviewed research from 2017 to mid-2025, provides the strongest evidence to date that vaping likely causes cancer independently.
Key Evidence from the Review
The review identified that the aerosol inhaled by vapers contains a complex mix of chemicals, including nicotine, its byproducts, and vaporised metals. This aerosol exhibits almost all of the ten "key characteristics of carcinogens" defined by the World Health Organization. Blood and urine analyses from vapers confirmed absorption of chemicals linked to cancer, such as carcinogenic metals from heating elements and organic compounds from e-liquids.
Furthermore, the study found evidence of DNA mutations in the mouth and lung tissues of vapers, indicating carcinogen exposure. Changes in cancer biomarkers, which precede tumor development, were also observed, including inflammation and oxidative stress. Additional support came from experiments on mice showing that vape aerosols caused lung cancer, and anecdotal reports from dentists linking oral cancers in non-smoking patients to vaping.
Implications and Shifting Perspectives
The evidence strongly suggests that nicotine-based vapes are likely to cause oral and lung cancer, though the exact number of future cases remains unknown. The review noted a significant shift in scientific conclusions over time: between 2017 and 2019, researchers often stated there was insufficient evidence to link vaping to cancer, but by 2024 and 2025, concerns grew, with many authors arguing that vaping could no longer be considered lower risk than smoking. This study represents a new approach by examining cancer caused by vaping in its own right, rather than as a gateway to smoking.
Unanswered Questions and Future Research
Direct evidence of increased cancer cases among vapers is still lacking, and it may take decades to establish a definitive link, similar to the timeline for smoking. Challenges include the need to study populations who only vape, not those who both smoke and vape. Large, carefully planned studies are essential to monitor and detect cancer early, determine precise causes, and potentially save lives through timely intervention. Funding and initiating such research now is critical for public health.
About the author: Bernard Stewart is a Professor in Paediatrics and Child Health at UNSW Sydney. This article was first published by The Conversation and is republished under a Creative Commons license.
