A review found cannabis has not been proven to cause lung cancer but evidence remains limited
A review in the Journal of Thoracic Oncology concluded that smoking cannabis has not been proven to increase lung cancer risk, while noting emerging evidence for cannabis as an adjunct in cancer symptom management, particularly for chemotherapy-induced nausea and pain.
Quick Facts
What This Study Found
Researchers reviewed the evidence on cannabis, lung cancer risk, and therapeutic applications in oncology.
On lung cancer risk: smoking cannabis has not been proven to be a risk factor for lung cancer development. However, the authors noted that existing studies are limited by small sample sizes, self-reporting errors, few heavy cannabis-only smokers in study populations, and confounding from concurrent tobacco use.
On therapeutic use: increasing evidence supports cannabis for managing chemotherapy-induced nausea and vomiting (CINV) and cancer-related pain. However, studies are limited by difficulties in standardizing doses and accurately measuring the biological activity of different cannabis compounds.
The authors called for controlled trials with standardized CBD and THC dosing to better establish both safety and therapeutic potential.
Key Numbers
Millions of regular cannabis users worldwide were referenced. No specific risk ratios for lung cancer were established due to insufficient data quality.
How They Did This
Narrative review of clinical and preclinical literature on cannabis, lung cancer, and cancer symptom management. Published in the Journal of Thoracic Oncology.
Why This Research Matters
With cannabis use rising and cancer patients increasingly asking about it, this review from a major oncology journal provides a balanced assessment. The finding that cannabis smoking has not been proven to cause lung cancer is notable, though the authors are careful to emphasize the limitations of existing evidence rather than declaring it safe.
The Bigger Picture
This review sits at the intersection of two important questions: whether cannabis use carries cancer risk, and whether it has therapeutic value for cancer patients. The honest answer to both is that better studies are needed, particularly randomized controlled trials with standardized dosing.
What This Study Doesn't Tell Us
Narrative review rather than systematic review or meta-analysis. Limited by the quality of underlying studies. The lung cancer safety question remains open rather than resolved.
Questions This Raises
- ?Would large, well-controlled prospective studies of heavy cannabis-only smokers reveal a lung cancer risk?
- ?What standardized cannabis formulations work best for CINV and cancer pain?
Trust & Context
- Key Stat:
- Smoking cannabis has not been proven to be a lung cancer risk factor
- Evidence Grade:
- Moderate. Published in a top oncology journal with balanced assessment, but limited by the quality of underlying primary studies.
- Study Age:
- Published in 2018. Cannabis-cancer research has continued, though large definitive trials remain scarce.
- Original Title:
- Cannabis Use, Lung Cancer, and Related Issues.
- Published In:
- Journal of thoracic oncology : official publication of the International Association for the Study of Lung Cancer, 13(4), 480-487 (2018)
- Authors:
- Jett, James, Stone, Emily, Warren, Graham, Cummings, K Michael
- Database ID:
- RTHC-01704
Evidence Hierarchy
Summarizes existing research on a topic.
What do these levels mean? →Frequently Asked Questions
Does this mean smoking cannabis is safe for the lungs?
Not exactly. The review found that cannabis smoking has not been proven to cause lung cancer, but the evidence is limited. Cannabis smoke contains many of the same carcinogens as tobacco smoke, and the absence of proof of harm is not the same as proof of safety.
Can cannabis treat cancer itself?
This review focused on symptom management (nausea, pain), not cancer treatment. While some preclinical research has explored anti-tumor effects of cannabinoids, this review did not make claims about cannabis treating cancer directly.
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Cite This Study
https://rethinkthc.com/research/RTHC-01704APA
Jett, James; Stone, Emily; Warren, Graham; Cummings, K Michael. (2018). Cannabis Use, Lung Cancer, and Related Issues.. Journal of thoracic oncology : official publication of the International Association for the Study of Lung Cancer, 13(4), 480-487. https://doi.org/10.1016/j.jtho.2017.12.013
MLA
Jett, James, et al. "Cannabis Use, Lung Cancer, and Related Issues.." Journal of thoracic oncology : official publication of the International Association for the Study of Lung Cancer, 2018. https://doi.org/10.1016/j.jtho.2017.12.013
RethinkTHC
RethinkTHC Research Database. "Cannabis Use, Lung Cancer, and Related Issues." RTHC-01704. Retrieved from https://rethinkthc.com/research/jett-2018-cannabis-use-lung-cancer
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.