Who could imagine that cannabis might one day offer hope as a cure for cancer? The United States government, that's who.
For the past 30 years, U.S. officials have willfully ignored clinical research indicating that marijuana can inhibit the growth of certain type of malignant tumors. However, the recent publication of a trio of clinical studies and a pair of scientific reviews have effectively blown the lid off "Cancergate," and revealed that pot's medical value may be far greater than ever presumed.
THE EMERGING EVIDENCE
Last year, five scientific journals published prominent articles trumpeting cannabinoids (compounds in marijuana) as potential anti-cancer agents.
- Clinical trial data published in January 2003 issue of the Journal of the American Society of Clinical Investigation that found cannabinoids significantly inhibit skin tumor growth in mice. Investigators of the study concluded, "The present data indicate that local cannabinoids administration may constitute an alternative therapeutic approach for the treatment of non-melanoma skin cancer."
- Clinical trial data published in the March 2003 issue of The FASEB Journal that found that the "local administration of a non-psychoactive cannabinoid inhibits angiogenesis (tissue growth) of malignant gliomas (brain tumors)."
- A clinical review in the October 2003 issue of the prestigious journal Nature Reviews Cancer that concluded that cannabinoids' "favorable drug safety profile" and proven ability to inhibit tumor growth make them desirable agents in the treatment of cancer. According to the review's author, tumors inhibited by cannabinoids include: lung carcinoma, glioma, thyroid epithelioma, lymphoma/leukemia, skin carcinoma, uterus carcinoma, breast carcinoma, prostate carcinoma, and neuroblastoma (a malignant tumor originating in the autonomic nervous system or the adrenal medulla and occurring chiefly in infants and young children).
- Clinical trial data published in the November 2003 issue of the Journal of Pharmacology and Experimental Therapeutics that found the administration of the cannabinoid cannabidiol (CBD) inhibits the growth of human glioma cells both in vitro (e.g., a petri dish) and in animals in a dose-dependent manner. Investigators concluded, "Non-psychoactive CBD produce[s] a significant antitumor activity both in vitro and in vivo, thus suggesting a possible application of CBD as an antineoplastic agent (something which prevents the growth of malignant cells.)"
- And finally, a clinical review in the December 2003 issue of the journal Expert Opinion on Therapeutic Targets that summarized "the demonstrated antitumor actions of cannabinoids," and elaborated on "possible avenues for the future development of cannabinoids as antitumor agents."
AND SUBSEQUENT MEDIA BLACKOUT
Despite these stunning findings, media coverage of them in North America has been virtually non-existent. As noted by Richard Cowan, editor of the website MarijuanaNews.com, "The New York Times, The Washington Post and Los Angeles Times all ignored this story, even though its newsworthiness is indisputable: a benign substance occurring in nature destroys deadly brain tumors."
Why the media blackout? For starters, all of these studies were conducted overseas. And secondly, not one of them has been acknowledged by the U.S. government.
U.S. KNEW IN '74… AND AGAIN IN '96!
This wasn't always the case. In fact, the first ever experiment documenting pot's anti-tumor effects took place in 1974 at the Medical College of Virginia at the behest of the U.S. government. The results of that study, immortalized in an August 18, 1974 Washington Post newspaper feature, were that "THC slowed the growth of lung cancers, breast cancers and a virus-induced leukemia in laboratory mice, and prolonged their lives by as much as 36 percent."
Despite these favorable preliminary findings, U.S. government officials banished the study, and refused to fund any follow up research until conducting a similar though secret study in the mid-1990s. That study, conducted by the U.S. National Toxicology Program to the tune of $2 million concluded that mice and rats administered high doses of THC over long periods had greater protection against malignant tumors than untreated controls. However, rather than publicize their findings, government researchers shelved the results which only became public one year later after a draft copy of its findings were leaked in 1997 to the journal AIDS Treatment News, which in turn forwarded the story to the national media.
Nevertheless, in the nearly eight years since the completion of the National Toxicology trial, the U.S. government has yet to fund a single additional study examining pot's potential as an anti-cancer agent.
SCIENCE IGNORED NO MORE
Fortunately, researchers at Madrid, Spain's Complutense University, School of Biology have generously picked up where U.S. researchers so abruptly left off. In 1998, the research team led by investigator Manuel Guzman discovered that THC can selectively induce program cell death in brain tumor cells without negatively impacting the surrounding healthy cells. Then in 2000, Guzman's team reported in the journal Nature Medicine that injections of synthetic THC eradicated malignant gliomas (brain tumors) in one-third of treated rats, and prolonged life in another third by six weeks. A commentary to the study noted that the results were the first to convincingly demonstrate that cannabis-based treatments may successfully combat cancer.
Today, Guzman believes that enough favorable clinical evidence exists supporting pot's anti-cancer properties to warrant clinical trials in humans. "The scientific community has gained substantial knowledge of the palliative and anti-tumor actions of cannabinoids during the past few years," Guzman wrote in the October 2003 issue of Nature Reviews Cancer. "Anti-tumor compounds should selectively affect tumor cells [and] it seems that cannabinoids can do this, as they kill [malignant] tumor cells but do not affect their non-transformed counterparts and might even protect them from cell death. … As cannabinoids are relatively safe compounds, it would be desirable that clinical trials using cannabinoids … could accompany [ongoing] laboratory studies to allow us to use these compounds in the treatment of cancer." Guzman concludes the article by noting that the Spanish Ministry of Health recently approved a human clinical trial the first ever aimed at investigating the effects of intracranially administered THC on the life expectancy of volunteers suffering from malignant brain tumors.
"Cannabinoid research continues to show tremendous potential in the treatment of cancer," summarizes University of Southern California professor Mitch Earleywine, author of the book Understanding Marijuana: A New Look at the Scientific Evidence. However, he laments that the "vast majority of this work originates outside the United States, often in countries that lack our economic and scientific advantages. Let's hope that our drug policy won't stymie the battle against the second leading cause of death in America."
Indeed. Let's not add a potential treatment for cancer to the ever-growing list of victims of pot prohibition.
August 17, 2004