Cannabis Plus Tobacco Smokers Had More Aggressive Lung Cancers Than Tobacco-Only Smokers | Research

The takeaway

Among 150 young lung cancer patients, 39% smoked both cannabis and tobacco, and these dual smokers had higher rates of rare aggressive tumors and emphysema compared to tobacco-only smokers.

People who smoke cannabis with tobacco, pulmonologists, oncologists treating young lung cancer patients.

17% aggressive cancers in dual smokers vs 4% tobacco-only

What the researchers found

In a prospective study of 150 lung cancer patients aged 60 or under, 39% smoked both cannabis and tobacco (CTSs), 52% smoked only tobacco (TSs), and 9% were nonsmokers. All cannabis smokers also smoked tobacco. Compared to tobacco-only smokers, dual smokers were younger (median 53 vs 56 years), had more rare and aggressive cancers (17% vs 4%, p=0.007), higher emphysema rates (64% vs 38%, p=0.003), and lower gas diffusion capacity (63% vs 70%, p=0.004). Cannabis use was heavy (median 26 years, 4 joints/day).

Why it matters

This is one of the first prospective studies to use biomarker-confirmed cannabis exposure in lung cancer patients. The finding that dual smokers develop more aggressive tumor types at younger ages is clinically significant, particularly as cannabis use increases globally and most cannabis smokers also use tobacco.

The numbers in context

150 patients. 39% cannabis+tobacco, 52% tobacco-only, 9% nonsmokers. Dual smokers: median age 53, 26 years cannabis use, 4 joints/day. Rare aggressive cancers: 17% vs 4% (p=0.007). Emphysema: 64% vs 38% (p=0.003). Chest pain at diagnosis: 22% vs 8% (p=0.03).

How the study worked

Multicenter prospective study of 150 consecutive patients aged 60 or under diagnosed with primary lung cancer (2021-2023). Smoking behaviors were self-reported and confirmed by hair testing for nicotine, cotinine, THC, and CBD. Patients were categorized as cannabis+tobacco, tobacco-only, or nonsmokers. Clinical features, tumor characteristics, and surgical outcomes were compared.

What this study cannot tell us

Cannot determine whether cannabis independently caused the worse outcomes since all cannabis users also smoked tobacco. Self-reported use despite hair test confirmation. Relatively small sample (N=150). Single-country study in France where cannabis is typically smoked mixed with tobacco.

How to read the evidence

Moderate: prospective design with biomarker-confirmed exposure, but small sample and inability to separate cannabis from tobacco effects.

When this study was published

2025 study (data from 2021-2023)

The bigger picture

The near-universal co-use of cannabis with tobacco in this population makes it difficult to isolate cannabis's independent effect. However, the significantly higher rates of emphysema and aggressive tumors suggest cannabis smoking adds risk beyond tobacco alone, consistent with the higher temperatures and deeper inhalation patterns of cannabis smoking.

Questions still open

Does cannabis smoking independently increase lung cancer risk, or does it amplify tobacco's effects? Would vaporized or edible cannabis show the same associations? Are the aggressive tumor types related to specific carcinogens in cannabis smoke?

Common questions

Does smoking cannabis cause lung cancer?

This study cannot answer that directly since all cannabis smokers also used tobacco. However, dual smokers had more aggressive cancers at younger ages than tobacco-only smokers, suggesting cannabis may add risk.

How was cannabis use confirmed in this study?

Beyond self-report, researchers used hair testing to detect THC, CBD, nicotine, and cotinine, providing objective confirmation of smoking behaviors.

Read the original research

The Impact of Dual Cannabis and Tobacco Smoking in Young Patients With Lung Cancer: Results From the Prospective "Environment and Lung Cancer" Study.

Chest

View on PubMed ↗Publisher’s paper ↗

Citation

Pradère, Pauline; Marinello, Arianna; Vasseur, Damien; Naltet, Charles; Moaca, Stefan; Le Pavec, Jérôme; Ghigna, Maria Rosa; De Montpreville, Vincent; Adam, Julien; Lacroix, Ludovic; Ben Salem, Fares; Caramella, Caroline; Planchard, David; Mercier, Olaf; Aldea, Mihaela; Alvarez, Jean Claude. (2025). The Impact of Dual Cannabis and Tobacco Smoking in Young Patients With Lung Cancer: Results From the Prospective "Environment and Lung Cancer" Study.. Chest. https://doi.org/10.1016/j.chest.2025.09.017