Etude: fumer du cannabis n'entraîne pas de cancer du poumon

[daniel]

Fumer du cannabis, "même intensément sur le long terme", ne cause pas de
cancer du poumon, des voies aériennes supérieures ou de l'oesophage,
rapporte Donald Tashkin à la réunion annuelle de l'International
Cannabinoid Research
Society.

Pubdate: Sat, 02 Jul 2005
Source: CounterPunch (US Web)
Column: Pot Shots
Copyright: 2005 CounterPunch
Contact: counterpunch@counterpunch.org
Website: http://www.counterpunch.org/
Details: http://www.mapinc.org/media/3785
Author: Fred Gardner
Cited: International Cannabinoid Research Society
http://www.cannabinoidsociety.org/
Cited: Center for Medicinal Cannabis Research http://www.cmcr.ucsd.edu/
Cited: California Cannabis Research Medical Group http://www.ccrmg.org/
Bookmark: http://www.mapinc.org/pot.htm (Marijuana)
Bookmark: http://www.mapinc.org/mmj.htm (Marijuana - Medicinal)
Bookmark: http://www.mapinc.org/find?232 (Chronic Pain)
Bookmark: http://www.mapinc.org/find?323 (GW Pharmaceuticals)

STUDY: SMOKING MARIJUANA DOES NOT CAUSE LUNG CANCER

Marijuana smoking -"even heavy longterm use"- does not cause cancer
of the lung, upper airwaves, or esophagus, Donald Tashkin reported at
this year's meeting of the International Cannabinoid Research
Society. Coming from Tashkin, this conclusion had extra significance
for the assembled drug-company and university-based scientists (most
of whom get funding from the U.S. National Institute on Drug Abuse).
Over the years, Tashkin's lab at UCLA has produced irrefutable
evidence of the damage that marijuana smoke wreaks on bronchial
tissue. With NIDA's support, Tashkin and colleagues have identified
the potent carcinogens in marijuana smoke, biopsied and made
photomicrographs of pre-malignant cells, and studied the molecular
changes occurring within them. It is Tashkin's research that the Drug
Czar's office cites in ads linking marijuana to lung cancer. Tashkin
himself has long believed in a causal relationship, despite a study
in which Stephen Sidney examined the files of 64,000 Kaiser patients
and found that marijuana users didn't develop lung cancer at a higher
rate or die earlier than non-users. Of five smaller studies on the
question, only two -involving a total of about 300 patients-
concluded that marijuana smoking causes lung cancer. Tashkin decided
to settle the question by conducting a large, prospectively designed,
population-based, case-controlled study. "Our major hypothesis," he
told the ICRS, "was that heavy, longterm use of marijuana will
increase the risk of lung and upper-airwaves cancers."

The Los Angeles County Cancer Surveillance program provided Tashkin's
team with the names of 1,209 L.A. residents aged 59 or younger with
cancer (611 lung, 403 oral/pharyngeal, 90 laryngeal, 108 esophageal).
Interviewers collected extensive lifetime histories of marijuana,
tobacco, alcohol and other drug use, and data on diet, occupational
exposures, family history of cancer, and various "socio-demographic
factors." Exposure to marijuana was measured in joint years (joints
per day x 365). Controls were found based on age, gender and
neighborhood. Among them, 46% had never used marijuana, 31% had used
less than one joint year, 12% had used 10-30 j-yrs, 2% had used 30-60
j-yrs, and 3% had used for more than 60 j-yrs. Tashkin controlled for
tobacco use and calculated the relative risk of marijuana use
resulting in lung and upper airwaves cancers. All the odds ratios
turned out to be less than one (one being equal to the control
group's chances)! Compared with subjects who had used less than one
joint year, the estimated odds ratios for lung cancer were .78; for
1-10 j-yrs, .74; for 10-30 j-yrs, .85 for 30-60 j-yrs; and 0.81 for
more than 60 j-yrs. The estimated odds ratios for oral/pharyngeal
cancers were 0.92 for 1-10 j-yrs; 0.89 for 10-30 j-yrs; 0.81 for
30-60 j-yrs; and 1.0 for more than 60 j-yrs. "Similar, though less
precise results were obtained for the other cancer sites," Tashkin
reported. "We found absolutely no suggestion of a dose response." The
data on tobacco use, as expected, revealed "a very potent effect and
a clear dose-response relationship -a 21-fold greater risk of
developing lung cancer if you smoke more than two packs a day."
Similarly high odds obtained for oral/pharyngeal cancer, laryngeal
cancer and esophageal cancer. "So, in summary" Tashkin concluded, "we
failed to observe a positive association of marijuana use and other
potential confounders."

There was time for only one question, said the moderator, and San
Francisco oncologist Donald Abrams, M.D., was already at the
microphone: "You don't see any positive correlation, but in at least
one category [marijuana-only smokers and lung cancer], it almost
looked like there was a negative correlation, i.e., a protective
effect. Could you comment on that?"

"Yes," said Tashkin. "The odds ratios are less than one almost
consistently, and in one category that relationship was significant,
but I think that it would be difficult to extract from these data the
conclusion that marijuana is protective against lung cancer. But that
is not an unreasonable hypothesis."

Abrams had results of his own to report at the ICRS meeting. He and
his colleagues at San Francisco General Hospital had conducted a
randomized, placebo-controlled study involving 50 patients with
HIV-related peripheral neuropathy. Over the course of five days,
patients recorded their pain levels in a diary after smoking either
NIDA-supplied marijuana cigarettes or cigarettes from which the THC
had been extracted. About 25% didn't know or guessed wrong as to
whether they were smoking the placebos, which suggests that the
blinding worked. Abrams requested that his results not be described
in detail prior to publication in a peer-reviewed medical journal,
but we can generalize: they exceeded expectations, and show marijuana
providing pain relief comparable to Gabapentin, the most widely used
treatment for a condition that afflicts some 30% of patients with HIV.

To a questioner who bemoaned the difficulty of "separating the high
from the clinical benefits," Abrams replied: "I'm an oncologist as
well as an AIDS doctor and I don't think that a drug that creates
euphoria in patients with terminal diseases is having an adverse
effect." His study was funded by the University of California's
Center for Medicinal Cannabis Research.

* * *

The 15th annual meeting of the ICRS was held at the Clearwater,
Florida, Hilton, June 24-27. Almost 300 scientists attended. R.
Stephen Ellis, MD, of San Francisco, was the sole clinician from
California. Los Angeles Farmacy operator Mike Ommaha and
therapist/cultivator Pat Humphrey showed up to audit the
proceedings... Some of the younger European scientists expressed
consternation over the recent U.S. Supreme Court ruling and the vote
in Congress re-enforcing the cannabis prohibition. "How can they
dispute that it has medical effect?" an investigator working in
Germany asked us earnestly. She had come to give a talk on "the role
of different neuronal populations in the pharmacological actions of
delta-9 THC." For most ICRS members, the holy grail is a legal
synthetic drug that exerts the medicinal effects of the prohibited
herb. To this end they study the mechanism of action by which the
body's own cannabinoids are assembled, function, and get broken down.
A drug that encourages production or delays dissolution, they figure,
might achieve the desired effect without being subject to "abuse..."
News on the scientific front included the likely identification of a
third cannabinoid receptor expressed in tissues of the lung, brain,
kidney, spleen and smaller branches of the mesenteric artery.
Investigators from GlaxoSmithKline and AstraZeneca both reported
finding the new receptor but had different versions of its
pharmacology. It may have a role in regulating blood pressure.

Several talks and posters described the safety and efficacy of
Sativex, G.W. Pharmaceuticals' whole-plant extract containing high
levels of THC and CBD (cannabidiol) formulated to spray in the mouth.
G.W. director Geoffrey Guy seemed upbeat, despite the drubbing his
company's stock took this spring when UK regulators withheld
permission to market Sativex pending another clinical trial. Canada
recently granted approval for doctors to prescribe Sativex, and five
sales reps from Bayer (to whom G.W. sold the Canadian marketing
rights) are promoting it to neurologists. Sativex was approved for
the treatment of neuropathic pain in multiple sclerosis, but can be
prescribed for other purposes as doctors see fit.

A more detailed report on the ICRS meeting will appear in the
upcoming issue of O'Shaughnessy's, a journal put out by California's
small but growing group of pro-cannabis doctors. To get on the
mailing list, send a contribution of any amount to the CCRMG
(California Cannabis Research Medical Group) at p.o. box 9143,
Berkeley, CA 94709. It's a 501c3 non-profit and your correspondent's
main source of income.

Meanwhile, Back in San Francisco...

The California contingent was en route to the ICRS meeting when
Marian Fry, M.D. and her husband, attorney Dale Schafer, were
arrested on federal charges of conspiring to provide marijuana to a
patient. On the same day, three San Francisco cannabis clubs were
raided by the DEA and 19 people -all Asians and a few Latinos-
charged with conspiracy to cultivate and distribute marijuana.
Affidavits allege that they grew cannabis in rented houses in S.F.,
the East Bay and the Peninsula for sale to dispensaries and on the
black market. Three men were charged with intent to sell ecstasy. (An
undercover agent allegedly had purchased 1,000 tabs from a man named
Enrique Chan. During the raids on 26 locations, a total of 50 tabs
were found on one individual.) The two alleged ringleaders, Richard
Wang and Vincent Wan, were charged with money laundering. Defense
lawyers say the alleged money laundering consisted of using
dispensary proceeds to underwrite the grow ops. At a July 1 detention
hearing, bail for Wang was set at $2 million. Wan has not yet been
apprehended or turned himself in.

Former district attorney Terence Hallinan is representing Sergio
Alvarez, who hired him several months ago after police raided a house
in the Sunset district where Alvarez was allegedly cultivating
marijuana. "I didn't know at the time that that would become part of
a conspiracy case," Hallinan said after the detention hearing.
Alvarez's bail was set at $500,000; his working-class parents are
putting up their modest Sunnyvale home as surety. Hallinan says that
every cannabis dispensary has links to a network of growers, and that
the decision to take down these three was an attempt to exploit
anti-Asian sentiment. "They asked themselves, 'Who will we start with
now that we've been given permission [by the U.S. Supreme Court's
ruling in the Raich case]? Let's go after the Chinese!' San Francisco
has more than a hundred-year history of anti-Chinese attitudes and
policies." Contemporary resentments towards Asians in San Francisco
center around their apparent economic successes. It's an impossibly
expensive housing market, and one occasionally hears non-Asians say,
with mixed admiration and envy, things like: "How can they arrive
from Hong Kong in 1995 and buy a house in the Sunset in 1996?" The
answer is: by pooling resources (conspiring) with friends and family
to make the down payment.

THE INNER SUNSET

I used to have the real estate knack

But all that I gaineth, I giveth back

Only to wind up with you in this cozy

Old shack in the Inner Sunset years

*

Obviously I did everything wrong

Except one or two that strung me along

The road to the club called Chez Nancy Wong

A shack in the Inner Sunset years

*

Where there's noodles at midnight

If you are in need of a treat

Where the Judah car makes an 'N'

'n careens down the street

*

I still believe that it's all within reach

A big enough place between here and the beach

And from each and according to each

A shack in the sunset in the sunset years

*

The blood orange sunset years

The cool gray sunset years
__________________________________________________________________________
Distributed without profit to those who have expressed a prior interest in
receiving the included information for research and educational purposes.
---
MAP posted-by: Richard Lake

[daniel]

Bulletin IACM du 26 Juillet 2005
-----------------------------------------



Science: Fumer du cannabis ne provoque pas de cancer
selon une étude à cas contrôlés

Selon une étude à cas contrôlés conduite par Dr. Donald
Tashkin et ses collègues de l'Université de Californie à Los
Angeles, même fumer beaucoup de cannabis à long terme
n'est pas associé au cancer du poumon et d'autres types
de cancer du système aérodigestif supérieur. Les résultats
ont été présentés le 26 Juin à la conférence annuelle de
l'ICRS (International Cannabinoid Research Society)

L'étude a impliqué 1209 résidents de Los Angeles âgés de
18 à 59 ans, atteints de cancer (611 concernant les
poumons, 403 les voies orales/pharynx, 90 le larynx et 108
l'oesophage). Les interviewers ont collecté des historiques
exhaustifs de consommation de cannabis, de tabac,
d'alcool et d'autres types et des données concernant
d'autres facteurs qui peuvent influencer le risque de cancer,
notamment le régime alimentaire, les expositions
professionnelles et les antécédents familiaux concernant le
cancer. L'exposition au cannabis a été mesurée en années-
joint (1 année-joint = 365 joints). Les patients atteints du
cancer ont été comparés à 1040 cas de contrôle non
atteints de cancer. Parmi les cas de contrôles, 46 pour cent
n'avaient jamais consommé de cannabis, 31 pour cent en
avaient consommé pour moins d'une année-joint, 12 pour
cent entre 10 et 30 années-joint, 2 pour cent entre 30 et 60
années-joint et 3 pour cent pour plus de 60 années-joint.

Comparé aux sujets ayant consommé moins d'une année-
joint, le risque de cancer du poumon était de 0,78 pour 1 à
10 années-joint, 0,74 pour 10 à 30 années-joint, 0,85 pour
30 à 60 années-joint, et 0,81 pour plus de 60 années-joint.
Un risque en dessous de 1,0 signifie que le risque pour les
consommateurs de cannabis est légèrement plus faible que
celui des non consommateurs. Des résultats similaires ont
été obtenus pour d'autres types de cancer. Il n'est pas
apparu de relation proportionnelle à la dose dans le risque
de cancer, ce qui signifie qu'il n'y avait pas d'augmentation
de risque pour les consommateurs les plus intensifs. Les
données sur la consommation de tabac, ainsi qu'on pouvait
l'attendre, ont mis en évidence un effet très puissant et une
relation proportionnelle à la dose assez nette.

(Source: Morgenstern H, et al. Marijuana use and cancers
of the lung and upper aerodigestive tract: results of a case-
control study. Présentation à la Conférence ICRS sur les
cannabinoïdes , 24-27 Juin, Clearwater, Etats-Unis)