Does Smoking Marijuana Increase the Risk of Lung Cancer? The Jury’s Still Out

Other Effects of Smoking Marijuana  

Dr Powell noted that there is evidence demonstrating stress and injury to the lungs after exposure to any smoked product, aside from the issue of lung cancer risk.2-4 

“Lung cells have strong capabilities to respond to injury, and the outcomes include full repair, cell death, airway inflammation, lung fibrosis, permanent changes to the cell DNA, and cancer,” Dr Powell explained. “These short-term and long-term responses can occur when smoking cigarettes, E-cigarettes, marijuana, cigars, and water pipes.”

Various factors determine an individual’s response to these exposures, according to Dr Powell. Susceptibility to lung injury and lung disease is determined, in part, by genetics, but there is a lack of data to enable prediction of which smokers will develop cancer. 

“My advice is not to smoke, period,” Dr Powell said. “There are alternative approaches to access marijuana other than through smoking, and there is no evidence to date—nor is there likely to be—that oral or topical use of marijuana products will injure the lungs.”

In the context of medical marijuana use for symptom relief in patients with cancer,10 however, Dr Abrams recommended that “if patients want better control over the onset, depth, and duration of the effect, inhaling is probably better than ingestion.”

“Further research is indicated to better understand the impact of different marijuana cigarette products and different approaches to smoke marijuana,” Dr Powell said. In addition to being useful for health care providers, “this information may be useful to those who cannot or will not quit,” he said.

Disclosures: Dr Abrams and Dr Powell have no relevant disclosures.

References

1. Berke J, Gal S, Lee YJ. Marijuana legalization is sweeping the US. See every state where cannabis is legal. Business Insider. Updated May 27, 2022. Accessed July 21, 2022. 

2. Cannabis (Marijuana) Research Report. What are marijuana’s effects on lung health? National Institute on Drug Abuse. Published July 2020. Accessed July 21, 2022.

3. Kaplan AG. Cannabis and lung health: Does the bad outweigh the good? Pulm Ther. 2021;7(2):395-408. doi:10.1007/s41030-021-00171-8

4. Tashkin DP. Effects of marijuana smoking on the lung. Ann Am Thorac Soc. 2013;10(3):239-247. doi:10.1513/AnnalsATS.201212-127FR

5. National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Board on Population Health and Public Health Practice; Committee on the Health Effects of Marijuana: An Evidence Review and Research Agenda. Chapter 5: Cancer. In: The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research. National Academies Press; 2017. 

6. Zhang LR, Morgenstern H, Greenland S, et al; Cannabis and Respiratory Disease Research Group of New Zealand. Cannabis smoking and lung cancer risk: Pooled analysis in the International Lung Cancer Consortium. Int J Cancer. 2015;136(4):894-903. doi:10.1002/ijc.29036

7. Callaghan RC, Allebeck P, Sidorchuk A. Marijuana use and risk of lung cancer: A 40-year cohort study. Cancer Causes Control. 2013;24(10):1811-1820. doi:10.1007/s10552-013-0259-0

8. Ghasemiesfe M, Barrow B, Leonard S, Keyhani S, Korenstein D. Association between marijuana use and risk of cancer: A systematic review and meta-analysis. JAMA Netw Open. 2019;2(11):e1916318. doi:10.1001/jamanetworkopen.2019.16318

9. Clark TM. Scoping review and meta-analysis suggests that cannabis use may reduce cancer risk in the United StatesCannabis Cannabinoid Res. 2021;6(5):413-434. doi:10.1089/can.2019.009510.

10. PDQ® Integrative, Alternative, and Complementary Therapies Editorial Board. Cannabis and Cannabinoids (PDQ®): Health Professional Version. National Cancer Institute. PMID:26389198. Updated June 7, 2022. Accessed July 21, 2022.

This article originally appeared on Cancer Therapy Advisor