Tuesday, August 18, 2009
Marijuana and Cancer Prevention
If Pot Prevented Cancer You Would Have Read About It, Right?
Posted: August 17, 2009 06:31 PM
Two just published studies assessing adults' risk of cancer have
reported wildly divergent, and fairly extraordinary, outcomes. One study
you may have read about. The other has been ignored entirely by the
mainstream media. But no doubt the results of both will surprise you.
First, the study you may have heard of. Writing August 3 in the journal
Cancer Epidemiology, investigators at McGill University in Montreal
reported that moderate alcohol consumption -- defined as six drinks or
fewer per week -- by adults is positively associated with an elevated
risk of various cancers, including stomach cancer, rectal cancer, and
And now for the study you haven't heard of. Writing in the August issue
of the journal Cancer Prevention Research, investigators from Rhode
Island's Brown University, along with researchers at Boston University,
Louisiana State University, and the University of Minnesota reported
that lifetime marijuana use is associated with a "significantly reduced
risk" of head and neck squamous cell carcinoma.
Authors reported, "after adjusting for potential confounders (including
smoking and alcohol drinking), 10 to 20 years of marijuana use was
associated with a significantly reduced risk of head and neck squamous
cell carcinoma (HNDCC)."
Perhaps even more notably, subjects who smoked marijuana and consumed
alcohol and tobacco (two known high risk factors for head and neck
cancers) also experienced a reduced risk of cancer, the study found.
"Our study suggests that moderate marijuana use is associated with
reduced risk of HNSCC," investigators concluded. "This association was
consistent across different measures of marijuana use (marijuana use
status, duration, and frequency of use)....Further, we observed that
marijuana use modified the interaction between alcohol and cigarette
smoking, resulting in a decreased HNSCC risk among moderate smokers and
light drinkers, and attenuated risk among the heaviest smokers and
This isn't the first time that U.S. investigators have documented an
inverse association between pot use and cancer. A separate 2006
population case-control study, funded by the U.S. National Institutes of
Health and conducted by the University of California at Los Angeles,
also reported that lifetime use of cannabis was not positively
associated with cancers of the lung or aerodigestive tract, and further
noted that certain moderate users of the drug experienced a reduced
cancer risk compared to non-using controls.
Predictably, the federal government's goal when green-lighting the UCLA
study was to conclusively establish just the opposite result, as
explained recently by its lead researcher Dr. Donald Tashkin.
In an interview with the McClatchy newspaper chain in June, Dr. Tashkin
admitted that he expected his study would find that pot was associated
with "increased health effects." Instead, he summarized, "What we found
instead was no association (between marijuana smoking and cancer) and
even a suggestion of some protective effect."
Tashkin added, "[A]t this point, I'd be in favor of (marijuana)
legalization. I wouldn't encourage anybody to smoke any substances. But
I don't think it should be stigmatized as an illegal substance. Tobacco
smoking causes far more harm. And in terms of an intoxicant, alcohol
causes far more harm (than marijuana)."
Despite these findings, which to date inexplicably remain under-reported
by the mainstream press, many so-called experts persist with claims that
marijuana smoking is causally linked to cancer. In fact, in June the
California Environmental Protection Agency with great fanfare added
marijuana smoke to its list of chemicals that possess potential
carcinogenic properties and/or are associated with reproductive
toxicity. You know what other commonly indulged in substance also
appears on this list? That would be alcohol. Of course that conclusion,
much like the reports of marijuana's anti-cancer prowess, apparently
went up in smoke.
Paul Armentano is the Deputy Director of the National Organization for
the Reform of Marijuana Laws (NORML) and is the co-author
of the new book Marijuana Is Safer: So Why Are We Driving People to
Drink? (Chelsea Green Publishing).
http://www.huffingt onpost.com/ paul-armentano/ if-pot-prevented -cancer-y_ b\