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.
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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.