E-cigarettes have long been marketed as a smoking-cessation aid, but new research suggests they may significantly increase the risk of lung and oral cancers. Most alarmingly, the risk spikes dramatically when conventional cigarettes and e-cigarettes are used together.
DNA Damage and Inflammation: The Hidden Risks
Researchers at the University of New South Wales in Australia conducted a comprehensive analysis of e-cigarette studies published between 2017 and 2025. Their findings indicate that e-cigarettes cause DNA damage and cellular dysfunction linked to cancer.
By damaging the airway lining and triggering chronic inflammation in lung tissue, e-cigarettes alter the delicate balance of microorganisms in the mouth. These changes increase oxidative stress, a known precursor to lung and oral cancers. Professor Bernard Stewart, who led the study, was blunt in his assessment: “E-cigarettes are by no means a safe substitute. It is difficult to view them as a safer choice.”
The "Dual-Use" Trap: A Fourfold Increase in Risk
The highest risk was observed among "dual users"—those who use both e-cigarettes and conventional cigarettes simultaneously. In this group, the risk of developing lung cancer increased by approximately fourfold. Given that many smokers turn to e-cigarettes as a bridge to quitting, this suggests that the attempt to quit may inadvertently heighten their health risks.
The researchers also highlighted the danger to younger populations, citing a rare case of a teenager developing oral squamous cell carcinoma after long-term e-cigarette use.
A Path Similar to Tobacco’s History
Co-author Professor Freddy Sitas noted that e-cigarettes may be following the same trajectory as traditional tobacco. “It took nearly 100 years to reach the conclusion that smoking causes lung cancer,” he said. “E-cigarettes should not be casually recommended without strict oversight.”
While e-cigarettes typically contain less tar and carbon monoxide than traditional cigarettes, they often contain harmful chemicals like formaldehyde, which can trigger inflammatory responses and DNA mutations. The findings were recently published in the international oncology journal Carcinogenesis under the title, “The carcinogenicity of e-cigarettes: a qualitative risk assessment.”
The Ongoing Debate: Harm Reduction or Hidden Hazard?
The medical community remains divided on the role of e-cigarettes. Professor Peter Hajek of Queen Mary University of London argues they remain one of the most effective tools for quitting, noting that they involve far lower exposure to carcinogens. Professor Lion Shahab of University College London (UCL) views them as a "harm-reduction strategy" for existing smokers but strongly advises non-smokers against starting the habit.
Prevention: The Key is Quitting Entirely
In South Korea, lung cancer remains the second most common cancer, accounting for 11.4% of all cases according to 2023 data. Approximately 90% of these cases are linked to smoking. Experts agree that while e-cigarettes may seem less harmful in the short term, the most effective prevention is to avoid smoking in all its forms.
Frequently Asked Questions
Q1. Are e-cigarettes safer than conventional cigarettes? E-cigarettes reduce exposure to tar and carbon monoxide, but they are not entirely safe. They contain toxic substances like formaldehyde, and their long-term health effects are not yet fully understood.
Q2. Is it more dangerous to use e-cigarettes and conventional cigarettes together? Yes. "Dual use" causes overlapping exposure to various toxins. Research indicates that using both simultaneously can quadruple the risk of lung cancer.
Q3. Can e-cigarettes directly cause lung or oral cancer? While a definitive causal link is still being researched, e-cigarettes have been proven to cause DNA damage, chronic inflammation, and oxidative stress—all of which are significant risk factors for cancer development.
