Donald P. Tashkin, M.D. et al. presented the study "Marijuana Use and Lung Cancer: Results of a Case-Control Study" at the American Thoracic Society International Conference on 5/24/06. The study was funded by the National Institute on Drug Abuse (NIDA), and involved 1,200 people in Los Angeles who had lung, neck or head cancer and an additional 1,040 people without cancer matched by age, sex and neighborhood. The study's abstract reported:
"Marijuana smoke contains several known carcinogens, heavy habitual use can produce accelerated malignant change in lung explants [removed living tissue]....
We therefore assessed possible associations between MJ use -- including heavy long-term use -- and the risk of lung cancer in middle-aged adults living in Los Angeles County....
Personal interviews were completed in 611 lung cancer cases & 1040 controls. Data were collected on lifetime use of marijuana, tobacco, alcohol & other drugs, SES, diet, occupation & family history of cancer. Logistic regression was used to estimate the effect of MJ use on lung cancer risk, adjusting for age, gender, race/ethnicity, education & cumulative tobacco smoking & alcohol use.
Conclusion: We did not observe a positive association of MJ use -- even heavy long-term use -- with lung cancer, controlling for tobacco smoking and other potential confounders."
5/24/06 Donald Tashkin
Dr. Tashkin additionally noted in a 5/26/06 article in the Washington Post titled "Study Finds No Cancer-Marijuana Connection" by Marc Kaufman:
"[The new findings] were against our expectations.
We hypothesized that there would be a positive association between marijuana use and lung cancer, and that the association would be more positive with heavier use. What we found instead was no association at all, and even a suggestion of some protective effect."
5/26/06 Donald Tashkin
The study was previously presented at the June 2005 meeting of the International Cannabinoid Research Society, and published on our site at that time as a response to the question "Does the regular smoking of marijuana cause lung cancer or in any way permanently injure the lungs?"