Marijuana occupies a complicated position among the substances used to alleviate symptoms associated with cancer and cancer treatment. On the one hand, most U.S. states have legalized cannabis (the plant from which marijuana is derived) for medical purposes. On the other hand, federal law prohibits the prescription or possession of marijuana.
Although cannabis has been used for medicinal purposes for millennia in some societies, and regulations are shifting, stigma around its use persists. It has made research and clinical application difficult while exacerbating issues of social justice and equity. Still, early research has shown it may be helpful for patients experiencing side-effects from chemotherapy like nausea. The bottom line for patients interested in using medical cannabis is to discuss its possible role with their care team.
Cannabis is not approved by the U.S. Food and Drug Administration (FDA) for any medical purpose, but some drugs with isolated compounds from cannabis have been approved. These discrepancies put cannabis in something of a gray zone for medical use.
Right now, there is no research showing that cannabis can effectively treat cancer. The strongest evidence suggests that it helps reduce nausea and vomiting that may be caused by some chemotherapies. According to the National Cancer Institute (NCI), certain chemicals in marijuana, including delta-9-THC, bind 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). Instead, they may be considered as a last line therapy if mainstream drugs do not work.
While research continues, cannabis can be most useful when viewed as an alternative supplement. Regulations and standards for cannabis products can vary from state to state. In Dana-Farber’s home state of Massachusetts, medical cannabis dispensaries are required to test their products and determine cannabinoid make-up and assure there aren’t contaminants (i.e. metals, fungus, or bacteria). Other states may not have similar regulations in place, and this should be discussed with your local health care provider.
More information is needed to make the case that cannabis is beneficial for other side-effects associated with cancer treatment. Moreover, there are a host of side effects associated with cannabis use itself, including potential problems with learning, memory and attention, and possible psychosis. Because cannabis smoke contains many of the same substances as tobacco smoke, there are also concerns about its effect on the lungs. It can cause respiratory issues and may increase your risk for developing lung cancer.
It is crucial to speak with your care team if you are using or considering using medical cannabis.
Asking your doctor about cannabis
Patients seeking recommendations around using cannabis face challenges. As the medical field navigates evolving findings and laws around cannabis, it can be difficult to find reliable information. Despite the rising prevalence of legal medical cannabis, the stigma around its use, and the effect of its prohibition, persists. 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. Inequities like these further complicate already sensitive discussions.
This is why transparency and respect between patients and medical providers are crucial. Trust within the clinic will ensure that both patient and provider are making the most-informed decisions. Your care team should be informed about any cannabis use because it may affect your treatment recommendations.
If you are interested in cannabis for cancer treatment side-effects, ask your oncologist. Let them know why you want to use cannabis and bring questions you might have about the research, how it will interact with your current medications, and what kind of 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.
For more information, watch this short video on cannabis use.