Behind the headlines: Will vaping really cause a 'new wave' of lung cancer?

Vaping could ‘wake up’ cancer cells, according to media reports about research into lung malignancies in non-smokers—but are these dramatic claims grounded in evidence?

In September 2022 dire warnings emerged that scientists were “raising alarm over a potential 'new wave' of cancer” and that “vaping may ‘wake up’ cancer cells and trigger wave of disease in a decade”.

It followed a research abstract presented at the European Society for Medical Oncology (ESMO) Congress 2022, entitled, Mechanism of action and an actionable inflammatory axis for air pollution induced non-small cell lung cancer.

This study looked at how cancer develops in the one-in-eight lung cancer patients who are non-smokers. The study so far has made impressive strides in understanding the mechanisms of lung cancer development—and possible avenues for prevention.^[]

But vaping isn’t mentioned in the research—so why did it feature so prominently in headlines?

Mechanisms of lung cancer development

The abstract shows results from part of the TRACERx Lung Study, a program to understand how lung cancer starts and develops over time.^[]

Researchers looked at 463,679 individuals in the UK, South Korea and Taiwan.^[] They identified a new mechanism where fine particulate matter (PM2.5) in the air trigger mutations in a gene called EGFR.4

These irritants cause inflammation followed by a healing process that activates certain cells in the lungs. These may grow and potentially form tumors.^[] Around 18-33% of normal lung tissues samples in non-smokers showed these genetic markers and the process was also investigated in mouse lung cancer models.^[]

These particulates are usually contained in air pollution and car fumes.^[]

Professor Charles Swanton, Cancer Research UK’s Chief Clinician and lead researcher for the study, stated in a press release: “Air pollution is associated with lung cancer, but people have largely ignored it because the mechanisms behind it were unclear.”^[] This research sheds light on how this mechanism functions, leading to much greater understanding of the disease and the impact of environmental factors.

Where does vaping come in?

Professor Swanton has been quoted by various news outlets as saying: “I don’t think we can say vaping is necessarily a safe option to quit smoking. It may be safer but that doesn’t mean it’s safe. We don’t know for certain that vaping won’t cause lung cancer ten years from now.”^[][]

But exactly how or why this connects with the rest of the research presented, or what prompted this commentary, is unclear from the reporting.

E-cigarette particulates can cause forms of indoor air pollution—including increasing concentrations of PM2.5—the air pollutant particulate matter which was examined in the study.

In response to Professor Swanton’s presentation, Professor Allan Balmain, a cancer geneticist at the University of California, San Francisco said the data presented was an insight into the mechanisms of ‘promoting substances’. These can prompt mutations in cells in the lungs and include cigarette smoke and air pollution. He added that “there is evidence that vaping can induce lung disease and cause inflammation similar to promoters”.^[]

However, no part of the data presented at ESMO looks at vaping as a cause of this irritation, despite the focus in media headlines.

The ESMO presentation coincided with a report from the Action on Smoking and Health (ASH), which stated that vaping in the UK is at record levels: about 8.3% of adults vape, rising from 1.7% only 10 years ago.^[] A third of adults in the UK believed vaping was more or equally as harmful as smoking - an assumption that ASH disputed.^[]

Missing the big picture

By focusing on Professor Swanton’s comments about vaping, media reports missed two of the important conclusions in this breakthrough research.

Firstly, researchers found that—at least in mice—the risk of mutations after air-pollutant exposure was mediated by an inflammatory protein, called interleukin-1 beta (IL1B). This could open up a new avenue for research into prevention or treatment.^[]

Professor Swanton concluded in an article for Cancer Research UK: “The mechanism we’ve identified could ultimately help us to find better ways to prevent and treat lung cancer in never smokers. If we can stop cells from growing in response to air pollution, we can reduce the risk of lung cancer.^[]

The research also cements the fundamental link between environment and health. Study co-author Dr. Emilia Lim from the Francis Crick Institute stated: “Even small changes in air pollution levels can affect human health,” and pointed out that “99% of the world’s population lives in areas which exceed annual WHO limits for PM2.5, underlining the public health challenges posed by air pollution across the globe”.^[]

Professor Swanton emphasized that though the risk of lung cancer from air pollution is lower than smoking, “we have no control over what we all breathe. Globally, more people are exposed to unsafe levels of air pollution than to toxic chemicals in cigarette smoke, and these new data link the importance of addressing climate health to improving human health.”^[]

Though there are still many questions around vaping and its long-term safety—and the understanding of this new mechanism could open up new avenues of research into this topic—there has been no concrete connection as of yet. Headlines surrounding this research chose to focus on vaping, where little new information has been found if any, yet missed two major points coming out of this important research.^[]