Can Marijuana Really Cure Cancer? Here’s The Science

The answer may surprise you!

cure cancer
Photo by Flickr user ryan melaugh

To delve into the literature on medical marijuana can, at times, feel like wading into a sea of nonsense. But one of the claims that seems on its face to rank among the most supremely bullshittiest turns out to be… an astonishing breakthrough that will astonish you: Cannabis actually can cure cancer.

Provided your cancer is a brain tumor, and you are a laboratory rat.

Let’s back up a sec. Cannabinoids—the active ingredients in marijuana, which include THC as well as nearly one hundred other related chemicals—work in the body by stimulating a network of receptors. Actually, it’s a series of networks. CB1 receptors, for instance, are found throughout the brain and nerve ends, while CB2 receptors congregate in the immune system. The first cannabinoid receptor was not found until the 1980s, and that was soon followed up with the discovery of endocannabinoids, the body’s own cannabis-like chemicals. Considering the relatively short time we have known about the endocannabinoid system and the obvious legal impediments to marijuana research, we know very little about what cannabinoids do and why we make them.

Nevertheless, the diversity and abundance of the endocannabinoid system is the chief physiological support for the concept of medical marijuana. Everything from mood disorders to nerve diseases to autoimmune illnesses may reasonably be speculated to have a potential cannabis treatment.

Cancer, though, does seem a stretch. First of all, it’s not one disease, but many, although they all manifest in uncontrollable, and sometimes fatal, cell growth. And secondly, cannabinoids play no known role in cell growth.

And yet, since the late 1990s, Dr. Manuel Guzmán, biology professor at Complutense University in Madrid, Spain, has been pursuing the question of whether the brain’s cannabinoid receptors, particularly in the brain, might defend against tumors. According to a series of studies Guzmán has co-authored, the answer might be “Yes.” In 15 years of treating brain tumors in lab mice with a chemical cocktail primarily composed of THC, Guzmán has seen cancer growth halted in one third of his subjects and—astonishingly!—it was reversed in another third, until the tumors were completely eliminated.

In 2006, Dr. Guzman published in The British Journal of Cancer the results of the first clinical trial on humans. Nine subjects with an aggressive form of brain cancer called “glioblastoma” that had resisted traditional interventions were treated with Guzmán’s THC mix. All nine responded at least partially. Such a small sample is, of course, statistically insignificant, but it does certainly suggest that further research is worthwhile.

You might want to pause before engaging in a little homegrown experimentation. Guzmán bathed his subjects’ tumors with a cannabinoid solution that was delivered via a catheter stuck directly into the brain—not the mellowest way to ingest weed. Alas, there is no evidence that smoked marijuana targets brain tumors or can deliver medically effective dosages.

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