Pubdate: Fri, 28 Aug 2009
Source: AlterNet (US Web)
Copyright: 2009 Independent Media Institute
Website: http://www.alternet.org/
Author: Fred Gardner
Note: Fred Gardner is the editor of O'Shaughnessy's 
http://www.ccrmg.org/journal.html , a quarterly journal of the 
California Cannabis Research Medical Group.
Referenced: More Evidence That Marijuana Prevents Cancer 
http://www.mapinc.org/drugnews/v09/n000/a170.html

SMOKING MARIJUANA DOES NOT CAUSE LUNG CANCER

New Research Shows Here Seems to Be Something in Pot That Actually 
Undermines Cancer, Instead of Causing It. -- And the Media Are Doing 
Their Best to Ignore It.

One in three Americans will be afflicted with cancer, we are told by 
the government (as if it's our immutable fate and somehow 
acceptable). Cancer is the second-leading cause of death in the U.S. 
and lung cancer the leading killer among cancers.

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.

Tashkin reviewed his findings in April 2008, at a conference 
organized by "Patients Out of Time," a reform group devoted to 
educating doctors and the public (as opposed to lobbying 
politicians). Some 30 MDs and nurses got continuing medical education 
credits for attending the event, which was held at Asilomar, on the 
Monterey Peninsula.

The National Institute on Drug Abuse, 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 found, however, disproved their 
hypothesis. (Tashkin is to marijuana as a cause of lung cancer what 
Hans Blix was to Iraq's weapons of mass destruction -- an honest 
investigator who set out to find something, concluded that it wasn't 
there, and reported his results.)

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." 
Tashkin reported them at the 2005 meeting of the International 
Cannabinoid Research Society. They were published in the October 2006 
issue of Cancer Epidemiology Biomarkers & Prevention.

Without a press release from NIDA calling attention to its 
significance, the assignment 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" by Mia 
Hashibe1, Hal Morgenstern, Yan Cui, Donald P. Tashkin, Zuo-Feng 
Zhang, Wendy Cozen, Thomas M. Mack and Sander Greenland was a 
blockbuster story.

I suggested to Eric Bailey of the L.A. Times that he write up 
Tashkin's findings -- UCLA provided the local angle if the 
anti-cancer effect wasn't enough. Bailey said his editors wouldn't be 
interested for some time because he had just filed a 
marijuana-related piece. The Tashkin scoop is still there for the taking!

Tashkin Defends His Findings

Investigators from New Zealand recently got widespread media 
attention for a study contradicting Tashkin's results. "Heavy 
cannabis users may be at greater risk of chronic lung disease 
- -including cancer- compared to tobacco smokers," is how BBC News 
summed up the New Zealanders' findings.

The very small size of the study -79 smokers took part, 21 of whom 
smoked cannabis only- was not held against the authors. In fact, the 
small New Zealand study was given much more coverage by the corporate 
press than the large UCLA study that preceded it.

The New Zealand study was portrayed as the latest word on this 
important subject. As if scientific inquiry were some kind of tennis 
match and the truth just gets truthier with every volley.

Tashkin criticized the New Zealanders' methodology in his talk at 
Asilomar: "There's some cognitive dissonance associated with the 
interpretation of their findings. I think this has to do with the 
belief model among the investigators and -I wish they were here to 
defend themselves- the integrity of the investigators... They 
actually published another paper in which they mimicked the design 
that we used for looking at lung function."

Tashkin spoke from the stage of an airy redwood chapel designed by 
Julia Morgan. He is pink-cheeked, 70ish, wears wire-rimmed 
spectacles. "For tobacco they found what you'd expect: a higher risk 
for lung cancer and a clear dose-response relationship. A 24-fold 
increase in the people who smoked the most... What about marijuana? 
If they smoked a small or moderate amount there was no increased 
risk, in fact slightly less than one. But if they were in the upper 
third of the group, then their risk was six-fold... A rather 
surprising finding, and one has to be cautious about interpreting the 
results because of the very small number of cases -- fourteen-- and 
controls -- four."

Tashkin said the New Zealanders employed "statistical sleight of 
hand." He deemed it "completely implausible that smokers of only 365 
joints of marijuana have a risk for developing lung cancer similar to 
that of smokers of 7,000 tobacco cigarettes... Their small sample 
size led to vastly inflated estimates... They had said 'it's ideal to 
do the study in New Zealand because we have a much higher prevalence 
of marijuana smoking.' But 88 percent of their controls had never 
smoked marijuana, whereas 36% of our controls (in Los Angeles) had 
never smoked marijuana. Why did so few of the controls smoke 
marijuana? Something fishy about that!"

Strong words for a UCLA School of Medicine professor!

As to the highly promising implication of his own study -that 
something in marijuana stops damaged cells from becoming malignant-- 
Tashkin noted that an anti-proliferative effect of THC has been 
observed in cell-culture systems and animal models of brain, breast, 
prostate, and lung cancer. THC has been shown to promote apoptosis 
(damaged cells die instead of reproducing) and to counter 
angiogenesis (the process by which blood vessels are formed --a 
requirement of tumor growth). Other antioxidants in cannabis may also 
be involved in countering malignancy, said Tashkin.

COPD

Much of Tashkin's talk was devoted to Chronic Obstructive Pulmonary 
Disease, 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 United States. Air pollution and 
tobacco smoke are known culprits. Inhaled pathogens cause an 
inflammatory response, resulting in diminished lung function. COPD 
patients have increasing difficulty clearing the airways as they get older.

Tashkin and colleagues at UCLA conducted a major study in which they 
measured lung function of various cohorts over eight years and found 
that tobacco-only smokers had an accelerated rate 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," said 
Tashkin. "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."

Breathe easier, everybody.

[sidebar]

Editor's Note: There is a groundswell of attention in the news to 
marijuana's role in causing and preventing various types of cancers. 
Last week, AlterNet published an article from the Marijuana Policy 
Project about a new study finding that pot smokers have a lower risk 
of head and neck cancers than people who don't smoke pot. Earlier 
this year, the corporate media pounced on a study suggesting that men 
who had been using marijuana at least once per week and who had 
started smoking pot prior to age 18 had an elevated risk of 
testicular cancer known as nonseminoma, which makes up fewer than 
half of one percent of all cancer cases among men.

Head, neck and testicular cancers are of course quite serious 
ailments to deal with, but what about cancer of the most obvious 
organ at risk with pot smoking, the lungs? Where's the science on 
that? The article below by Fred Gardner, editor of the medical 
marijuana research quarterly journal O'Shaughnessy's, shares the 
results of a major medical study the media completely ignored, and 
his conclusions are quite blunt on the matter: Smoking pot doesn't 
cause lung cancer. In fact, the study found that cigarette smokers 
who also smoked marijuana were at a lower risk of contracting lung 
cancer than tobacco-only smokers.
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MAP posted-by: Richard Lake