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Dr. John Leonard: Welcome to Weill Cornell Medicine CancerCast, conversations about new developments in medicine, cancer care and research. I'm your host, Dr. John Leonard and today on the podcast, we will be talking about medicinal marijuana for cancer patients.

Our guest for this episode is Dr. Michelle Loy, who's an Integrative Medicine Physician at Weill Cornell Medicine and New York Presbyterian Hospital. Dr. Loy is Certified in Integrative Medicine, Lifestyle Medicine, Medical Acupuncture, as well as Pediatrics. She uses nutrition, movement and holistic medicine to help prevent and manage chronic illnesses.

Her research focuses on the mind-body connection, as well as the use of nutrition, acupuncture, stress management, and botanical medicine to support cancer prevention and recovery. Dr. Loy currently serves as an Executive Committee Member for the Section of Integrative Medicine for the American Academy of Pediatrics.

Today, I'm looking forward to focusing our conversation on medical marijuana as part of an integrated approach to cancer care. So, Dr. Loy, thank you so much for joining us today. It's great to have you. This is a topic that comes up a lot for cancer patients, and I'm really looking forward to your discussion about how this modality of treatment can be helpful to patients. So thank you joining us today.

Dr. Michelle Loy: Thank you for having me.

Dr. John Leonard: So, the area of integrative medicine is one that is in some ways relatively recent and also expanding and is something that lots of patients have interest in and have derived benefit from. So maybe if you could tell us a little bit about in a general sense, what is this particular field and what drew you to working in this area amongst all the different areas of medicine?

Dr. Michelle Loy: So I always say the seeds for integrative medicine were sewn from my birth in that while I was born in the US, my paternal grandfather was born at the turn of the century in a small village in Taishan Guangdong province in China. Yet I consider he was a man ahead of his time, and he had immigrated to the US and then obtained his medical degree from the Kansas City College of Osteopathy and Surgery in about 1927. Then my maternal grandmother regularly did T'ai chi ch'üan. And when visiting my grandparents in Asia as a child, I would remember being given these traditional Chinese medicine soups for various conditions and even in the US, I grew up on a mostly traditional Chinese diet.

At the same time, I was infused with a strong reverence for science and evidence-based medicine. Since my father is a research scientist in the US and my mom is a registered dietician. So even early in my preclinical years at Cornell Medical College, I sought out additional training in nutrition research related to garlic, turmeric, and cancer. And then after doing my pediatric residency at Cornell, and then close to two decades of treating complex medical conditions and lifestyle related illnesses within general peds, I decided to pursue fellowship training in adult and pediatric integrative medicine. And got some additional certifications as well in medical acupuncture and medical yoga.

Personally, my family also passed through a life-threatening medical crisis that was oncology related during which we received state of the art treatment and the highest level of care from multi-disciplinary team at Weill Cornell and during the treatment and recovery phases, we benefited greatly from the various integrative medicine approaches.

So fast-forward to today, I am privileged to offer integrative medicine consultations at my Alma Mater and have pioneered an integrative oncology group visit series entitled Living Well With and After Cancer. And during this series, we discuss topics of interest to patients, including food as medicine, botanicals, vitamin supplements, culinary herbs, traditional Chinese medicine herbs, medicinal mushrooms, acupuncture, movement, mindfulness, yoga, narrative medicine, and of course, medical cannabis.

Dr. John Leonard: You've touched on a number of areas of integrative medicine and I know we could probably have an entire episode on each of them. But I'd like to focus on the issue of medical marijuana or medical cannabis. Maybe if you could start by defining the terms or the different forms of marijuana or its derivatives that are used in this setting to support patients with cancer and other illnesses and how that differs from what some people may use recreationally.

Dr. Michelle Loy: Medical cannabis is generally used to refer to a large variety of cannabis products, including dry leaf products and tinctures of isolated cannabinoids, which is cannabidiol also known as CBD, used for medicinal purposes. And it differs from recreational marijuana in that it is used as medicine.

So when marijuana is used as medicine, it is highly regulated by the state. And each state has its own regulation concerning which diagnoses and symptoms are approved. So for New York State, historically, the list has included seizures, multiple sclerosis, Parkinson's, IBD, PTSD, chronic pain, substance abuse, HIV, ALS and cancer. Recently, actually in January of 2022, the qualifying conditions were actually expanded by the New York State Office of Cannabis Management, so that patients are no longer limited by a list of qualifying conditions to be eligible for the use of medical cannabis. And so the patient's certifying practitioner can use his or her clinical discretion to issue a certification for the medicinal use of cannabis. So, patients with Alzheimer's or spinal cord injury or muscular dystrophy or dystonia or rheumatoid arthritis, autism, or really any other condition based on the practitioner's clinical discretion may qualify.

Unlike recreational marijuana, the medical cannabis dispensing facilities in New York State are strictly regulated by the Office of Cannabis Management. And so the OCM requires independent laboratory testing for every brand of product for any contaminates and to ensure product consistency.

Dr. John Leonard: Is the New York State process, and I know we don't have time to get into every state in detail, but is that the general approach for most states? Or is New York State an outlier in one way or another, as far as how this is managed? What's the general trend across the country for this sort of scenario?

Dr. Michelle Loy: That's a great question. New York State is quite representative of many of the other states. The process is very similar on how to certify.

Dr. John Leonard: So you named a number of different conditions where cannabinoids could be potentially helpful. It's kind of amazing that it has, or potentially has, such a broad effect. Like many therapeutics so to speak, there are lots of different mechanisms of action but more or less how biologically does cannabis help such a broad array of conditions at a very high level.

Dr. Michelle Loy: So cannabis, is actually a genus of a flowering plant native to Asia with three subspecies of sativa, indica, and ruderalis and actually over 400 chemical compounds are produced in the plant with 65 unique to the cannabis plant.

So the phytocannabinoids of most therapeutic interest are tetrahydrocannabinol, which is THC and cannabidiol CBD. So marijuana and hemp have the same genus cannabis and species sativa but the amount of THC differs where hemp has 0.3% and marijuana has between 6 and 20%. THC causes the psychoactive effects of getting high. Cannabidiol or CBD which does not cause those psychoactive effects, but has shown some positive effects on other certain body symptoms, including seizure reduction.

Now, besides the two major ones, most well-known cannabinoids, THC and CBD, there are a number of minor cannabinoids like CBG, CBN, that more and more research is being done on.

Like other botanicals, like other plants, there are also other biological compounds included in cannabis, which many people don't know about. And that includes broadly speaking, terpenes, carotenoids, fatty acids, sterols, vitamin E and triglycerides. Now there are two really interesting points about terpenes.

One is that the terpenes are responsible for the different aromas in the different types. And the second is that many of these terpenes in cannabis are also found in other botanicals and foods, including pine needles, lavender, black pepper, hops, citrus, carrots, chocolate.

The same terpene in hops contributes to the same sedative muscle relaxing effects in the indica type of cannabis. And the same terpene in citrus and cannabis is responsible for the anti-anxiety, the anti-depressant, and the GERD relieving effects, and the same terpene that's in black pepper and cannabis has pain relieving, so analgesic anti-inflammatory effects and also protection to the GI lining. So many of these the biological compounds, including the terpenes, may be responsible for some of the beneficial effects of cannabis. So, back at THC and CBD, these are the two most well-known cannabinoids. And you may ask what are cannabinoids?

Well in simplest terms, the cannabinoid is any substance that can join with the cannabinoid receptors in the body and produce effects very similar to those of the cannabis sativa plant. So in our body, we have CB1 receptors, mostly in the brain and peripheral nervous system. And we have CB2 receptors in our immune cells, our fat tissue, our muscle and our livers, spleen, bones, intestines, all over the body.

CB1 receptors regulate sleep, pain, appetite, metabolism, emesis, cognition, reward, the immune system, muscular pain and ocular pressure. And CB2 receptors are responsible for immune health, inflammation, cell proliferation, pain, and GI motility. So THC and CBD as well as the other more minor cannabinoids bind to the CB1 and CB2 receptors in our body with different affinities. And when the receptors are activated, the effects may include changes in the neurotransmitter levels, reduction in inflammation and changes in metabolism.

Now, one other really interesting topic is the topic of endocannabinoids. We also now know that every single organ in the body has both CB1 and CB2 receptors that receive endocannabinoids. And in 1992, the researchers at the National Institute of Mental Health in Bethesda discovered that our body actually makes its own natural cannabinoids, just like it makes its own endogenous opiates. So these endocannabinoids that are derived from omega-6 fatty acids are thought to be very important for keeping our body in balance, what we know as homeostasis. And two examples of these endocannabinoids include anandamide and 2-AG. It's really interesting that patients with pain and anxiety, migraine, fibromyalgia, IBD have been shown to be endocannabinoid and anandamide deficient.

And the other thing is the endocannabinoids are also now thought to be responsible for the runners high. So, there is an interesting question, can phytocannabinoids stimulate the endocannabinoid system without cannabis? And the thought is possibly. There are many foods that are rich in endocannabinoids. And some examples include carrots, oregano, echinacea, clove, black pepper, flax and saffron. And remember I mentioned earlier that there are biological compounds such as terpenes that are very common between cannabis and plants and foods. It's interesting, chocolate has been identified to contain anandamide compounds. And that might be one reason that people enjoy eating it so much.

The other important thing about endocannabinoid foods is what we call the plant's entourage effect, meaning that the sum is greater than the parts. So possibly creating more benefit and reducing risk. And that's why the marketing people often like to use the term full spectrum product.

Dr. John Leonard: Given all of the different medical conditions and the different effects of cannabis potentially, it seems like one could argue just about everybody should take it or take some version based on what they're dealing with, but clearly that's not the case.

Amongst the millions of cancer patients how would someone decide or at least ask the question, is this type of therapy useful to me or potentially useful to me as we open the door to thinking about it.

Dr. Michelle Loy: Let me start with who should or shouldn't really consider medical marijuana. There are some contraindications, and they include the following: Active psychosis or active substance abuse should not, it's not recommended in pregnancy or breastfeeding. Pregnant women, who smoke it, it’s shown to increase the risk that their baby may be born with a lower birth weight.

There is no minimum or maximum age, but the neuroplasticity of the brain under age 25 is a concern. And there are legitimate concerns about the potential negative effects of the developing adolescent brain, including short-term memory loss, decreased concentration, a decline in school performance and possible increased risk for future problematic cannabis use disorders and psychosis.

If it's medically necessary and we weigh the risk and benefits, an oral dosing can be safer and easier. Other risks include the unknown effects of chronic use on the developing brain. Again, some evidence of increased likelihood of compulsive use when recreational use is started in adolescence. And again, long-term cannabis smoking can cause chronic breathing problems.

There are a number of diseases where treatment with medical marijuana have been shown to be very effective, specific seizure syndrome disorders in children, chemotherapy-induced nausea, vomiting, chronic pain, and multiple sclerosis spasticity. For these conditions, there has been quite a bit of evidence that the effects are quite modestly effective. In fact, for chemotherapy induced nausea and vomiting, the oral cannabinoids have been shown to be as effective as anti-emetics and in adults with chronic pain, patients who are treated with cannabis or cannabinoids are more likely to experience a clinically significant reduction in pain symptoms.

Dr. John Leonard: If I'm a patient or a practitioner taking care of a cancer patient, and I think the patient can potentially benefit from this form of therapy; and I would, assume in most cases, it's, let's say a patient with nausea or pain, that's getting the standard therapies, the standard pharmacologic therapies that we give in an oncology practice. And then perhaps those are either causing side effects or not working well enough. It would seem like that's a scenario where I might say to a patient or the patient might say, gee, can I explore a form of cannabis to try to help me even better manage these symptoms. Is that the typical scenario in your practice and I guess logistically, how does that work? I know I've referred you some patients, but let's talk a little bit about the process for the patient as they go into this and at least consider this modality.

Dr. Michelle Loy: So again, the process for getting medical marijuana is state dependent. Interested patients should go on their particular state's medical marijuana website, and the websites have a directory with the providers trained in prescribing medical marijuana. And like you mentioned, patients can ask their oncologist or their primary care doctor for recommendations.

So after the patient meets with the provider, meets with us and discuss the condition and the symptoms, then we may certify you for medical marijuana and this, at least in New York State, and this is pretty characteristic of other states, the certification process can be done very easily, online or over the phone.

And then the patient will get a medical marijuana card in the mail, or they can actually even print it online and they can bring that medical marijuana card, which is known as the patient registry ID card, and now, in New York State, you can have up to five designated caregivers, can go to the local dispensary, present the patient registry ID card and the government issued ID and purchase the product at the dispensing facility. In New York State, these products are not available at a regular pharmacy but there are many of these dispensing facilities around.

Dr. John Leonard: When you give the prescription do you specifically designate what the form of the cannabinoid is that you're administering? Do you decide, does the patient decide, how does one choose between one form or the other?

Dr. Michelle Loy: That's a great question. So, the practitioner can put in recommendations for the form or the dosing but they can also leave it up to the pharmacist consultation. When we counsel our patients, we always tell them to meet with the pharmacist at the formulary and share their history and their preferences. Because as you know, there are many different approved forms of medical marijuana. So some examples of the New York State approved forms include a vape cartridge or pen, capsules or tablets, tinctures, which are liquids that go under the tongue, oral spray, oral powder, lozenges, metered ground plant preparation for vaporization, even transdermal patches

Medical marijuana may not be incorporated into food products by the registered organization unless approved by the commissioner. And smoking is not an approved route of administration.  

So yes, the practitioner can make some recommendations, but also patients often have preferences. And some of that may be dictated by their medical condition. So for example, patients with severe pain who can't tolerate anything by mouth, anything orally, because maybe they're nauseous or vomiting. And perhaps they may not have access to IV medications at home, then the vaping form of the medical marijuana can be very helpful.

And just so patients know this is very different from vaping tobacco. The vaping pen delivers the medical marijuana oil in a vapor. So it doesn't have any of the harmful substances that you would typically see in other recreational vaping. The different forms of medical marijuana also have different what we call pharmacodynamics. So what the substance does to the body and pharmacokinetics, what the body does to the substance. So this can affect the bioavailability, the timing to the peak concentration, the way the liver metabolizes. So depending on pre-existing conditions or personal preferences, patients can discuss this with their providers and pharmacists.

We counsel the patients to be open, to try different forms as there can be different individual variations in response. Just like with any botanical. And in addition to the dose and the tolerance and strain, the mode of administration needs to be tailored to the individual patient. We are very fortunate in New York State to have a variety of options to offer patients.

Dr. John Leonard: Are there particular interactions between medical marijuana and other drugs that one should be careful about? I would think at some level that certain pain medicines or other areas might give some sort of overlapping side effects. Is that a concern?

Dr. Michelle Loy: Yes. Absolutely. Thank you for bringing that up. There are definitely interactions with drugs and other medicines. So we do caution against mixing medical cannabis with anti-coagulants, immunotherapy, anti-epileptics, alcohol and certain medications like theophylline. Mostly because the enzymes within the liver can be affected. Now people often ask about cannabinoids and opioids and yes, they do share several pharmacologic properties. Anti-pain, sedation, hypotension, things like that. And in one cancer trial 20 milligrams of oral THC, which is pretty high, was comparable to a codeine of 120 milligrams, but with marked psychological effects.

It has been shown that THC can greatly enhance the NLDS against active morphine in a synergistic fashion in animal model. So there was a thought, could there be the possibility of enhancing the analgesic effect at lower opiate doses.

There's an interesting study in 2011, a small study done by Abrams in 21 patients with chronic pain and they concluded that co-administration of vaporized cannabis with oral sustained release opioids is safe. And actually co-administration of the vaporized cannabis on subjects with stable doses of morphine or oxycodone appeared to enhance the analgesia and the co-administration of the vaporized cannabis trended towards lowering the concentration of the opioids.

There was actually one study in elderly patients, it was a prospective study of more than 2,700 Israeli elderly patients using cannabis. And their mean age was about 74 and their most common indications were pain, 66% of them and cancer, which was 60% of them. And 93% of the respondents reported improvement in their condition. And the reported pain level was reduced from a median of eight on a scale of zero to 10, to median of four after six months of treatment.

And there were minimal adverse events, just dizziness in 9% and dry mouth in 7%. But what was most interesting to me, it was that after six months, 18% of them were able to stop using opioid analgesics or reduce their dose. So that's pretty interesting.

Dr. John Leonard: We talked a bit about drug interactions. What about side effects that people should keep an eye out for if they try medical marijuana? I would think that it's probably hard to sort out because patients with cancer who are taking this form of therapy also are on chemotherapy in many cases, lots of other drugs. Are there certain things that are pretty attributable to the cannabinoids?

Dr. Michelle Loy: Yeah, it's tricky because as you mentioned, they are dealing with a lot of different symptoms from possibly different causes, but the common side effects we usually mention, at least to look out for are: so in the cardiovascular system, they can sometimes experience tachycardia, palpitations, either hypertension or hypotension, maybe some vasodilation, respiratory, maybe some coughing or wheezing, in the neurologic, possibly some dizziness, some lethargy, some sedation, things like that. But most commonly, a little bit of nausea and dry mouth. But often if they try different forms of administration and different dosing, a lot of these side effects can be very minimal or not at all.

I should mention there's also the cannabinoid hyperemesis syndrome, which usually only occurs in individuals with long-term high dose cannabis use. And the onset is usually years after initiating cannabis use. And it's characterized by a chronic cannabis use with cyclic episodes of nausea and vomiting. And this cannabinoid hyperemesis syndrome has been linked to Delta-8 THC, which is mostly produced synthetically. And there's been more of a bigger jump in the poison control calls related to Delta-8 THC.

And one reason may be that that form may contain contaminants, harmful chemicals in concentrated forms, but usually that's not the kind you would get at the medical formulary.

Dr. John Leonard: I'd like to wrap up with a little bit of advice for patients. If you are a patient let's say, or a family member of a patient where some of the symptoms we've talked about are an ongoing and significant issue where you think that the idea of taking medical cannabis could be helpful or at least want to explore the possibility, what do you suggest to patients as far as bringing it up with their physicians? Particularly if it's a medical oncologist who may be less directly involved with this type of therapy, maybe less experienced or familiar. Do you have any suggestions for patients? Do you just bring it up? Do you search it out on your own? How would you suggest a patient really address this, if they think it could be helpful for them?

Dr. Michelle Loy: Yeah, this happens all the time in my practice. I think the best way is to think of it as one of the many tools in the toolbox. And many times patients either are struggling with anxiety or insomnia, which is very common with a diagnosis or during treatment. Especially if they're in the recovery phase and post-cancer, they want to avoid alcohol for health reasons. They may report that medical cannabis could help with social lubrication in patients with pain. Medical cannabis is very good for not only short-term treatment, but also a longer-term treatment, even post chemo radiation. Oftentimes patients can suffer from neuropathy, which is very difficult to treat.

And patients with poor appetite either from chemotherapy or nausea or mouth ulcers may be looking at other kinds of pharmaceuticals to try to manage its problems. But I would say medical cannabis is one way of, with one botanical, being able to address multiple symptoms.

Patients may have preconceived notions about it. But once we explain that it is a botanical, just like an herb or plant, used in a proper setting under the proper guidance, it can be very helpful from a quality of life perspective. And even more importantly, can help the patients with various symptoms adhere to the regimen that the oncologist is recommending to be the very best for the patient.

Dr. John Leonard: Well, thank you very much, Dr. Loy, this has been a great discussion and you've also pointed out the importance of cancer care at a center that can provide multidisciplinary treatment and support such as at Weill Cornell and New York Presbyterian Hospital, where you and your colleagues at the integrative medicine group, really can assess the symptoms and the challenges that patients are facing and try to tailor a supportive care approach, whether it's medical cannabis or other areas that you touched on earlier in order to help patients navigate these challenges of cancer care. So thank you for your insights today.

I'd like to invite our audience to download, subscribe, rate, and review CancerCast on Apple podcasts, Google podcasts, Spotify, or online at weillcornell.org. We also encourage you to write to us at This email address is being protected from spambots. You need JavaScript enabled to view it., with questions, comments, and topics you'd like to see us cover more in depth in the future.

That's it for CancerCast, conversations about new developments in medicine, cancer care and research. I'm Dr. John Leonard. Thanks for tuning in.

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