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Cancer Mythbusters: What to Know About Marijuana

  • Where does marijuana come into play when it comes to treating cancer? And can it help patients manage cancer? We dive into these questions, and other common questions, myths, and misconceptions about marijuana and cancer, with Ilana Braun, MD, chief of Adult Psychosocial Oncology at Dana-Farber Cancer Institute.

    Read the transcript:

    MEGAN: Hi. I'm Megan Riesz, and this is Cancer Mythbusters, a podcast from Dana-Farber Cancer Institute about the many myths and misconceptions in the world of cancer. Every episode, we'll take a look at a myth and debunk it with the help of our world-leading clinicians and researchers.

    For thousands of years, marijuana, also known by names such as pot or weed, has been used for medicinal purposes. A psychoactive drug, marijuana is an illegal drug under U.S. federal law; however, some states have legalized medical and recreational marijuana on their own. Dana-Farber Cancer Institute’s home state of Massachusetts legalized the drug in 2016.

    So where does marijuana come into play when it comes to treating cancer? And can it help patients manage cancer? We’re diving into these questions, and other common questions, myths, and misconceptions about marijuana and cancer, with Dr. Ilana Braun, Chief of Dana-Farber’s Adult Psychosocial Oncology Service.

    Thank for joining us, Dr. Braun.

    DR. BRAUN: Thanks for having me.

    MEGAN: To start off, a common question we often get is whether marijuana can cure cancer or can have a role in controlling cancer. What’s the answer here?

    DR. BRAUN: So, in clinical practice, I definitely encounter patients who are using medical marijuana with the intent to treat their cancer. The evidence, though, is really, really early. In preclinical studies, some of marijuana’s active ingredients have been shown to slow tumor growth through multiple mechanisms, so, for instance, inhibition of blood vessel growth or inhibition of signaling pathways.

    There is one really small study. It was a clinical trial on humans that demonstrated that marijuana could be successfully introduced into a brain tumor, but this was a feasibility study, so it was questioning whether or not it was even possible to do that at all rather than an effectiveness study, all this to say the jury is still out.

    MEGAN: So, can marijuana provide relief from some side effects of cancer treatment?

    DR. BRAUN: Well, there there’s a bit more evidence. Marijuana contains more than 300 active ingredients. Some of these are called cannabinoids and cannabinoids have achieved FDA approval for management of such things as chemotherapy-induced nausea and vomiting or unwanted weight loss. The latter is in HIV/AIDS patients, but we can extrapolate the cancer.

    There’s also a body of evidence to suggest that medical marijuana is helpful in the management of pain, mainly for what we call neuropathic pain, and these studies were largely done on patients with illnesses other than cancer. High-quality clinical trials on cancer patients are really necessary and are still lacking.

    MEGAN: So, should patient every use marijuana to relieve side effect without consulting their physician?

    DR. BRAUN: No. Oncology teams oversee the management of cancer fighting and symptom management treatments, and they should definitely be informed of any agent used for that purpose even when it is a complementary alternative medicine intervention like medical marijuana.

    MEGAN: Can we talk about some of the risks of using marijuana the patient should know about and whether those benefits outweigh the risks?

    DR. BRAUN: So, marijuana does carry some risks. It can cause respiratory issues such as chronic bronchitis, problems with learning and memory and attention. It can cause breaks from reality, what we call psychosis, suicidality and, of course, motor vehicle crashes. And people do get high from it.

    MEGAN: Many patients at Dana-Farber come from Massachusetts, but there are some that come from out of state. Can you talk about what these patients’ options are for medical marijuana use?

    DR. BRAUN: The Massachusetts regulation is really clear on this. Massachusetts-based physicians or nurse practitioners must certify Massachusetts residents to use medical marijuana that is only grown in Massachusetts, and patients from other states must consult their laws and adhere to them.

    MEGAN: Even if medical marijuana is legal in a state, do you think that the added legalization of recreational marijuana plays a role in terms of access and usage for cancer patients? And would you say that some patients might find it difficult to actually obtain a medical marijuana prescription?

    DR. BRAUN: It would be interesting to watch how the adult use laws affect marijuana use in Massachusetts. We need to study this for a while. I suspect that the market for medical marijuana will persist. There are many people who want the oversight of a medical professional and the imprimatur of a medicinal agent.

    MEGAN: Is there anything else you think patients should know about marijuana use?

    DR. BRAUN: Well, I just want to reemphasize that if a cancer patient is considering using medical marijuana, they shouldn’t be shy about raising this possibility with their oncology and other providers, and partnering with them in the decision-making.

    MEGAN: Great. Thanks so much for joining us, Dr. Braun.

    DR. BRAUN: This was a lot of fun. Thanks.

    See all Cancer Mythbusters episodes

  • Psychosocial Oncology
  • Coping with Cancer