The Marijuana Cancer Cure Cult

In his 1971 State of the Union speech, President Richard Nixon declared war on cancer, prompting passage of the National Cancer Act, aimed at making the "conquest of cancer a national crusade." Just four years later, scientists from the National Cancer Institute published a study demonstrating that a group of compounds taken from a common, widely cultivated plant shrank lung tumors that had been implanted in mice, extending their survival.

In a world that made sense, this plant and the anticancer drugs it produced would have been rushed into further testing, and we'd have known in a few years whether they had potential as treatments for human cancers. Instead, research proceeded at a glacial pace, with almost no further progress till the 1990s. Since then, vast quantities of lab and animal data have confirmed those early findings, but studies of these plant compounds in actual human beings with cancer remain nearly nonexistent.

What got in the way was Nixon's other war, the "war on drugs." The plant in question was cannabis sativa -- marijuana -- public enemy number one in that other war, and discovering that marijuana had beneficial properties was the last thing the U.S. government wanted to do.

Dr. Manuel Guzman of Complutense University in Madrid, lead author of the only human study yet published of a cannabinoid as cancer treatment, puts it slightly more diplomatically. The lack of immediate followup to those early reports "remains a mystery to me," he says. Guzman cites a number of obstacles to human trials, including the fact that cannabinoids are "still seen by many doctors and regulatory agencies as drugs of abuse," as well as "lots of paperwork" and a lack of commercial interest in natural compounds that can't be patented.

Complicating things further, the relative vacuum created by the lack of human studies and the hostility of the U.S. government to the whole question of marijuana's beneficial effects has left the field wide open for zealots who promote cannabis as a "cure" for cancer as if it were already a proven fact rather than a possibility in desperate need of serious study.

A Protective Effect?

Instead of researching cannabinoids as anticancer drugs, federal officials have continued to falsely imply that marijuana causes lung cancer. For example, a 2002 brochure for parents, "Talk to Your Child About Marijuana," still available on the Office of National Drug Control Policy Web site, advises, "Smoking marijuana is as least as bad as smoking cigarettes."

In fact, the largest, most well-controlled studies have consistently failed to find an increased risk of lung cancer or other typically tobacco-related cancers among marijuana smokers. These include a 65,000-patient 1997 study conducted at Kaiser Permanente in Oakland, California and a 2006 case-control study (in which patients with cancer were matched with similar patients without cancer to compare risk factors) from the UCLA lab of Dr. Donald Tashkin, one of the world's leading experts on the pulmonary effects of drugs.

In the UCLA study, there was a consistent trend -- albeit short of statistical significance -- toward lower cancer risk among even the heaviest marijuana smokers. This was a surprise to some, given that marijuana smoke contains many of the same carcinogenic compounds as tobacco smoke. The researchers wrote:

 

Although purely speculative, it is possible that such inverse associations may reflect a protective effect of marijuana. There is recent evidence from cell culture systems and animal models that 9-tetrahydrocannabinol, the principal psychoactive ingredient in marijuana, and other cannabinoids may inhibit the growth of some tumors by modulating key signaling pathways leading to growth arrest and cell death, as well as by inhibiting tumor angiogenesis. These antitumoral associations have been observed for several types of malignancies including brain, prostate, thyroid, lung, and breast.

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