By Paul Armentano
For 35 years, the federal government has been well aware – despite public denials by its own officials – that cannabis possesses potent anti-cancer and anti-tumor properties. Sadly, even under the Obama administration, which promised to “base our public policies on the soundest science,” the myth that pot promotes cancer persists. In fact, the White House’s Web site,, currently warns: “Marijuana has the potential to promote cancer of the lungs and other parts of the respiratory tract.”
Or not.

In a clinical abstract published by the medical journal Cancer Prevention Research in July, a team of US investigators reported – with absolutely no fanfare in the mainstream media – that lifetime marijuana use is associated with a “significantly reduced risk” of head and neck squamous-cell carcinomas.


Investigators at Rhode Island’s Brown University, along with researchers at Boston University, Louisiana State University and the University of Minnesota, assessed the lifetime marijuana-use habits of 434 cases (patients diagnosed with head and neck squamous-cell carcinomas at nine medical facilities) compared to 547 matched controls, and reported that, “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 (HNSCC).”


Perhaps even more notably, subjects who consumed alcohol and tobacco (two known high-risk factors for head and neck cancers) and smoked marijuana also experienced a reduced risk for the cancers, the study found.


“Our study suggests that moderate marijuana use is associated with reduced risk of HNSCC,” the 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 drinkers.”


Of course, this isn’t the first time that researchers in the US have documented an inverse association between pot use and cancer. A separate 2006 population case-control study, funded by the 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 recently explained by its lead researcher, Dr. Donald Tashkin.


In an interview with the McClatchy newspaper chain in June, Tashkin admitted that he expected the study would find “a positive association between marijuana use and lung cancer …. What we found instead was no association at all, and even a suggestion of some protective effect.”


Perhaps that explains why mention of Tashkin’s study – the largest of its kind – is curiously absent from the White House Web site.


Tashkin added: “[A]t this point, I’d be in favor of legalization. I wouldn’t encourage anybody to smoke any substances, because of the potential for harm. 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.”


As the co-author of the new book Marijuana Is Safer: So Why Are We Driving People to Drink?, I couldn’t agree more. When will the White House get the message? Perhaps when the president decides to put down his beer.


Paul Armentano is the Deputy Director of NORML and the co-author of Marijuana Is Safer: So Why Are We Driving People to Drink?