Newshawk: Kirk
Pubdate: Sat, 02 Jul 2005
Source: CounterPunch (US Web)
Column: Pot Shots
Copyright: 2005 CounterPunch
Contact: counterpunch@counterpunch.org
Author: Fred Gardner
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.
