Early research has shown cannabis may be helpful for patients experiencing side effects from chemotherapy and other types of cancer treatment, such as nausea and vomiting. But there are also risk associated with using cannabis, and the persisting social stigma and legal questions surrounding its use complicate how it is approached in a clinical setting.
Most U.S. states have legalized cannabis (the plant from which marijuana is derived) for medical purposes, including every state in New England: Massachusetts, New Hampshire, Connecticut, Maine, Rhode Island, and Vermont. But federally, marijuana is illegal.
Navigating the many questions around cannabis use requires transparency and trust between patients and their care team. Because it has become more ubiquitous, Dana-Farber is dedicated to providing up to date guidance. A recent panel of American Society of Clinical Oncology (ASCO) experts led by Dana-Farber Division of Adult Psychosocial Oncology Chief Ilana Braun, MD, recently published guidelines for providers and the use of cannabis in an oncology setting.
The bottom line is that patients using cannabis, or patients who are interested in using it, should have a discussion with their care team about the latest research, how it may interact with other medications including chemotherapy and immunotherapy, and its legality.
How can cannabis help?
Online, you’ll find various claims about the benefits of cannabis, including that it can be used to treat cancer itself. However, oncologists agree there is no evidence that cannabis can effectively treat cancer alone or in conjunction with conventional treatments. In fact, some studies have suggested that cannabis use can inhibit the effects of some immunotherapies.
Research reviewed by the ASCO panel primarily supports the use of cannabis to treat some symptoms of chemotherapy, mainly nausea and vomiting. Chemicals in marijuana, called cannabinoids, have been observed binding to brain cell receptors that help control nausea and vomiting.
However, evidence does not suggest that FDA-approved drugs containing cannabinoids, like dronabinol and nabilone, work better than other anti-nausea drugs like ondansetron (Zofran). So, drugs containing cannabinoid should be considered as a last line therapy if mainstream drugs do not work. While research continues, cannabis can be most useful viewed as an alternative supplement.
Potential risks
Regulations and standards for cannabis products can vary from state to state. In Massachusetts, where many Dana-Farber clinics are located, medical cannabis dispensaries are required to test their products for contaminants (i.e. metals, fungus, or bacteria) and determine their cannabinoid make-up. Other states may have different regulations in place, and this should be discussed with your local health care provider.
Moreover, there are a host of side effects associated with cannabis use itself, including potential problems with learning, memory and attention, and possible psychosis. Researchers are also concerned about possible reactions with other medications, including immunotherapies used to treat some cancers.
Cannabis may also have physical side effects. One study found that regularly taking high doses (over 300 mg) of cannabidiol (CBD) caused reversible liver dysfunction.
Social justice
Cannabis has been used for medicinal purposes for millennia in some societies, and while regulations are shifting, stigma around its use persists. This has made research and clinical application difficult, while social justice and equity issues have been exacerbated.
For example, a 2020 American Civil Liberties Union report concluded that, despite legalization, Black people continue to be disproportionately incarcerated for cannabis-related crimes despite similar rates of use among white people. This kind of disparity can add a layer of fear and mistrust around these conversations.
The recent ASCO guidelines seek to begin remedying stigma and bring providers up to date. But more work is needed. In a recent study by Braun, 80 percent of oncologists surveyed said they discussed medical cannabis with a patient, but only 30 percent felt qualified to offer recommendations for its use. Braun and her team found that many patients were getting most of their advice on medical cannabis from non-medical sources, like dispensary personnel.
Transparency and respect between patients and medical providers are crucial, and trust within the clinic will ensure that both patient and provider are making the most informed decisions.
Talk to your care team
It is crucial to speak with your care team if you are using or considering using medical cannabis. Let them know why you want to use cannabis and bring questions you might have about how it will interact with your current medications, the latest research, and what options you have to address your symptoms. They will know what’s possible in your state.
There are some providers at Dana-Farber formally registered with Massachusetts to certify
patient to receive cannabis, but some providers may need to refer you to someone with more
expertise.