Can Marijuana Help With Breast Cancer?

In 1996, when California became the first state in the Union to legalize the use of marijuana for medical purposes, a trend was started. Twenty years later, marijuana, also called cannabis -- referring to the dried leaves, flowers, stems and seeds of the Cannabis sativa plant -- can legally be used as a medication in 29 states and the District of Columbia, Governing magazine reports. In addition, seven states and the District have gone a step further and "have adopted the most expansive laws legalizing marijuana for recreational use. Most recently, California, Massachusetts, Maine and Nevada all passed measures in November [2016] legalizing recreational marijuana," the magazine reports.

Although marijuana can be legally used in many places now, it's still against federal law to use the drug, and the Food and Drug Administration has not approved its use to treat any medical condition. But some researchers are working to find out if marijuana could be a potential breast cancer treatment down the road. For now, the Drug Enforcement Agency lists marijuana as a Schedule I drug under federal drug schedules created when President Richard Nixon signed the Controlled Substances Act of 1970. Schedule I controlled substances "have a high potential for abuse, have no acceptable medical use in the U.S. and are unsafe when used under medical supervision," the DEA reports. Heroin, LSD, ecstasy and peyote are also classified as Schedule I drugs.

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Nevertheless, in many states across the U.S. marijuana has begun to emerge as a potential medication, with a lot of patients and some doctors supporting its wider adoption based on miraculous-sounding anecdotal success stories. The drug is primarily used to treat chronic pain and nausea, but some doctors are prescribing marijuana to treat a host of other conditions, and delivery of the medication can come as a liquid -- in tinctures or beverages; as a solid -- in food, called "edibles"; or as a gas -- through smoking.

The American Cancer Society reports that cannabinoids are the "biologically active components in marijuana." The two cannabinoids we know most about are delta-9-tetrahydrocannabinol, better known as THC, and cannabidiol, or CBD. THC "seems to cause the 'high' reported by marijuana users, and also can help relieve pain and nausea, reduce inflammation and can act as an antioxidant," the ACS reports. On the other hand, "CBD can help treat seizures, can reduce anxiety and paranoia, and can counteract the 'high' caused by THC." The levels of these compounds vary depending on the cultivar, or type, of marijuana being used, so different strains may be indicated for addressing a particular issue more than other strains.

The ACS notes that "dronabinol, a pharmaceutical form of THC, and a man-made cannabinoid drug called nabilone are approved by the FDA to treat some conditions." But using the leafy, smoked variety most Americans are familiar with is still illegal as far as the federal government is concerned.

In addition to THC and CBD, there are other compounds within marijuana that are being studied, but already, studies conducted at the California Pacific Medical Center Research Institute in San Francisco are showing promise in the use of cannabidiol to fight breast cancer specifically. A 2007 study published in the journal Molecular Cancer Therapeutics showed that CBD could slow or even stop the progression of metastatic breast cancer. In the study the team led by senior scientist Dr. Sean D. McAllister used CBD to inhibit the activity of the Id-1 gene, believed to be responsible for cancer cells becoming more aggressive and metastatic. "Metastasis is the final and fatal step in the progression of breast cancer," the authors write. "Currently available therapeutic strategies at this stage of cancer progression are often nonspecific, have only marginal efficacy and are highly toxic."

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Although the study was done in a lab on cells, not in actual live humans -- which could yield different results -- it showed that CBD could be a potential treatment to slow the growth and reduce the invasiveness of aggressive, metastatic cancers that currently respond to few if any available treatments. Further work by the team in animals has shown that cannabinoids may have antitumor effects, but more research is needed to fully understand the mechanisms of how these plant compounds can influence the biology of cancer.

At this stage, most doctors would likely agree that it's too soon to say that marijuana can treat breast cancer directly and that marijuana should -- like other alternative or holistic therapies -- only be used as a complement to your prescribed course of treatment, if at all. The ACS notes, "relying on marijuana alone as treatment while avoiding or delaying conventional medical care for cancer may have serious health consequences." But when used as a complement, many people report marijuana helps alleviate the nausea and pain associated with chemotherapy treatment. Some patients have also had success using marijuana to address the nerve pain associated with chemo-induced peripheral neuropathy.

But it's important to note that marijuana can bring its own side effects, including bloodshot eyes and dry mouth, slowed reflexes and decision making, disorientation and dizziness, increased heart rate, mood changes, increased appetite and possibly addiction. The National Institute on Drug Abuse reports "recent data suggest that 20 percent of those who use marijuana may have some degree of marijuana use disorder," also known as "problem use ... which takes the form of addiction in severe cases." About 4 million people in the U.S. "met the diagnostic criteria for marijuana use disorder" in 2015, the NIDA reports.

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Critics of the legalization of marijuana for medical or recreational use often point to its potential as a "gateway drug," meaning that it can lead to the use of other addictive drugs. The NIDA reports that although some research suggests that marijuana may "'prime' the brain for enhanced responses to other drugs," in most people, it's not an issue. "Also, cross-sensitization is not unique to marijuana. Alcohol and nicotine also prime the brain for a heightened response to other drugs and are, like marijuana, also typically used before a person progresses to other, more harmful substances."

If you're interested in using medical marijuana to address some of the side effects of treatment for breast cancer and you live in a state where it's available, be sure to speak with your doctor first. You'll need a medical marijuana card, which requires a doctor's evaluation, before you can access a dispensary. And if you do use it, be sure to communicate with your doctor about how best to do so.

Elaine K. Howley is a freelance Health reporter at U.S. News. An award-winning writer specializing in health, fitness, sports and history, her work has appeared in numerous print and online publications, including AARP.org, espnW, SWIMMER magazine and Atlas Obscura. She's also a world-record holding marathon swimmer with a passion for animals and beer. Contact her via her website: elainekhowley.com.