Worth Repeating: Smoking Cannabis Does Not Cause Lung Cancer


Photo: YouTube
Dr. Donald Tashkin of UCLA conducted the largest-ever study of marijuana’s effect on the lungs. His team found that not only was cannabis not associated with lung cancer, but that it possibly even exerts a protective effect against it.

‚ÄčFellow Tokers, meet Ron Marczyk, who’ll be bringing to your attention stories from the cannabis archives that are “Worth Repeating.”

Often, as stories are churned through the media’s 24-hour news cycle, good information flashes by and is lost. We aim to help correct that with “Worth Repeating,” which will cover important cannabis stories that you may have missed.
Ron is a retired health education teacher who taught health ed and psych (drug/sex ed) to high school students for 20 years. He is an R.N. (emergency room) M.S. in cardiac rehab, and worked as a New York City Police officer for two years.

Welcome, Ron!
Worth Repeating
by Ron Marczyk
Greetings to all you Toke readers. I greatly enjoy reading and researching past medical studies and news to help counter misinformation on the subject of cannabis.
Because of our very busy lives and the sheer volume of news coming at us on a daily basis, many important cannabis news stories are not reported, get buried, or are forgotten.
In this new Toke column I will be reintroducing such stories for your education and enjoyment.
Our next big chance to legalize is in 2012! So the next time you are discussing or debating with others you’ll have empirical data (facts/conclusions derived from scientific/medical studies) on your side.
This first story Worth Repeating was reported by Fred Gardner on AlterNet, August 28, 2009.
Smoking Marijuana Does Not Cause Lung Cancer
(and may even offer some protection against cancer!)
Conclusion/findings from “Marijuana Use and the Risk of Upper Aerodigestive Tract Cancers: Results of a Population-Based Case-Control” by Prof. Donald Tashkin, University of California at Los Angeles
You’d think it would have been very big news in June 2005 when UCLA medical school professor Donald Tashkin reported that components of marijuana smoke — although they damage cells in respiratory tissue — somehow prevent them from becoming malignant.
In other words, something in marijuana exerts an anti-cancer effect!
Tashkin has special credibility. He was the lead investigator on studies dating back to the 1970s that identified the components in marijuana smoke that are toxic.
It was Tashkin, et. al., who published photomicrographs showing that marijuana smoke damages cells lining the upper airways. It was the Tashkin lab’s finding that benzpyrene — a component of tobacco smoke that plays a role in most lung cancers — is especially prevalent in marijuana smoke.
It was Tashkin’s data showing that marijuana smokers are more likely than non-smokers to cough, wheeze, and produce sputum.
The National Institute on Drug Abuse (NIDA), which supported Tashkin’s marijuana-related research over the decades, readily gave him a grant in 2002 to conduct a large, population-based, case-controlled study that would prove definitively that heavy, long-term marijuana use increases the risk of lung and upper-airways cancers.
What Tashkin and his colleagues unexpectedly found, however, disproved their hypothesis.
Tashkin’s team interviewed 1,212 cancer patients from the Los Angeles County Cancer Surveillance program, matched for age, gender, and neighborhood with 1,040 cancer-free controls. Marijuana use was measured in “joint years” (number of years smoked times number of joints per day).
It turned out that increased marijuana use did not result in higher rates of lung and pharyngeal cancer, whereas tobacco smokers were at greater risk the more they smoked. Tobacco smokers who also smoked marijuana were at slightly lower risk of getting lung cancer than tobacco-only smokers.
These findings were not deemed worthy of publication in “NIDA Notes,” which had apparently been counting on results proving marijuana’s harmfulness.
Without a NIDA press release calling attention to its significance, the editors of America had no idea that “Marijuana Use and the Risk of Lung and Upper Aerodigestive Tract Cancers: Results of a Population-Based Case-Control Study” was a blockbuster story.
Marijuana Doesn’t Cause COPD, Either
The accelerated development of chronic obstructive pulmonary disease — COPD — is another condition prevalent among tobacco smokers. Chronic bronchitis and emphysema are two forms of COPD, which is the fourth-leading cause of death in the U.S. Air pollution and tobacco smoke are known culprits.
Tashkin and his UCLA colleagues conducted a major study in which they measured the lung function of various cohorts over eight years and found that tobacco-only smokers had an accelerated level of decline, but marijuana smokers — even if they smoked tobacco as well — experienced the same rate of decline as non-smokers.
“The more tobacco smoked, the greater the rate of decline,” Tashkin said. “In contrast, no matter how much marijuana was smoked, the rate of decline was similar to normal.”
Tashkin concluded that his and other studies “do not support the concept that regular smoking of marijuana leads to COPD.”