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ASCO: You’re listening to a podcast from Cancer.Net. This cancer information website is produced by the American Society of Clinical Oncology, known as ASCO, the voice of the world's oncology professionals.

The purpose of this podcast is to educate and to inform. This is not a substitute for professional medical care and is not intended for use in the diagnosis or treatment of individual conditions. Guests on this podcast express their own opinions, experience, and conclusions. Guests’ statements on this podcast do not express the opinions of ASCO. The mention of any product, service, organization, activity, or therapy should not be construed as an ASCO endorsement. Cancer research discussed in this podcast is ongoing, so data described here may change as research progresses.

Greg Guthrie: Hi everyone, I'm Greg Guthrie, a member of ASCO's patient education content team, and I'll be your host for today's podcast. ASCO is the American Society of Clinical Oncology, and we're the world's leading professional organization for physicians and oncology professionals caring for people with cancer. Today we're going to be talking about what patients should know about cannabis, cannabinoids, and cancer. ASCO recently published a clinical practice guideline on cannabis and cannabinoids for adults with cancer.

I'm happy to have 2 of the co-chairs from the committee that developed this guideline as our guests today. Dr. Ilana Braun is an associate professor at Harvard Medical School. Thanks for joining us, Dr. Braun.

Dr. Ilana Braun: Thanks so much for having me.

Greg Guthrie: It's a pleasure to have you here today. And Dr. Eric Roeland is an associate professor of medicine at Oregon Health and Science University. Welcome Dr. Roeland.

Dr. Eric Roeland: Thanks, Greg.

Greg Guthrie

Great. So before we begin, I want to note that neither Dr. Braun nor Dr. Roeland have any relationships to disclose related to this podcast, but you can find their full disclosures in this podcast's show notes.

So let's start with the fundamental question about this discussion, and that is what is a clinical practice guideline and how does it help guide cancer care? Dr. Roeland, can you start with this?

Dr. Eric Roeland: Of course, yeah. A clinical practice guideline describes the best practices or what clinicians call the “standard of care” with regard to a specific topic. So this is kind of the blueprint that clinicians use to guide their practice when taking care of people with cancer. And the American Society of Clinical Oncology clinical practice guideline on the use of cannabis and/or cannabinoids summarizes the best available data collected specifically from humans in clinical trials, and we combined that with a multi-disciplinary panel of expert opinion.

Greg Guthrie: Yeah, I think it's really important to always remember that best evidence comes from research in humans as well as from clinical expertise. So it's the best recommendations that we can have to support cancer care.

 

Dr. Eric Roeland: Greg, I also think it's very important to understand that there are different places that we gain knowledge in research. One is specifically when we are trying to figure out how a drug works, and we will test that in what we call “preclinical models,” which is usually within animals. And then, once we’ve determined safety and efficacy, then we start taking that information and approach studies in humans. And so when our listeners are learning about new data in the use of cannabis or cannabinoids, I encourage everyone to always stop and ask, is this data coming from the animals or is this from humans?

Greg Guthrie: That's such an important point. And I think it's so essential to always look for that piece of evidence whenever you're reading about scientific advances. Alright, so let's take a moment to talk about what it means when we say cannabis and cannabinoids. Dr. Braun?

Dr. Ilana Braun: Cannabis, which is better known as marijuana, is a plant that humans have turned to for thousands of years as a medicine, in manufacturing—for instance, in the making of rope­—and for enjoyment.

It's often mistakenly viewed as having one main ingredient, tetrahydrocannabinol, or THC, but it actually has more than 300 ingredients that act in the body. Some of those ingredients are referred to as cannabinoids. There are 2 cannabinoids of greatest interest, THC, which I just mentioned, and CBD, cannabidiol. THC is responsible for the high feeling some people experience with cannabis. CBD is not.

Currently in the U.S., some cannabis products containing these cannabinoids can be sourced at the pharmacy, others at cannabis dispensaries, and some through more informal means.

Greg Guthrie: That's great. Thank you for that definition here as we continue this discussion. So what do people with cancer typically think cannabis and cannabinoids will do to help them? Dr. Roeland?

Dr. Eric Roeland: Well, it's a great question, Greg, because in clinic, when patients and their loved ones express interest in either starting cannabis or cannabinoids or are currently using them, I always want to explore what their goal of use is. And interestingly, the goals of use are far-reaching. And I have heard everything from, to help with everything, to cure my cancer. And so it's incredibly important to understand why people are reaching towards these products, to understand what their goals are. If they're focused on using this to treat the underlying cancer, or instead of standard cancer therapies, we have grave concerns about this approach. And it may lead to worse outcomes of your cancer.

However, if cannabis or cannabinoids are being used to help with controlling some symptoms during their cancer treatment, it may be helpful. And especially in one particular case where people have really bad nausea and vomiting that persists despite our best medicines to prevent it.

Greg Guthrie: Thank you for that, Dr. Roeland. Dr. Braun, did you have anything to add?

Dr. Ilana Braun: Maybe I will just point out that decisions on what to target with cannabis are often made through trial and error or in consultation with dispensaries, but not as much as I would prefer in consultation with clinical teams.

Dr. Eric Roeland: So I would also add that it's incredibly important to bring these topics up with your clinical team because although cannabis and cannabinoids are considered safe by many because they're quote “natural,” it's important to recognize that they actually can interact with many of the other medications that you're already taking.

For example, patients with cancer might be experiencing really bad pain or anxiety and taking things like opioids or benzodiazepines. And when you combine that with cannabis, it can prolong some of the effects of sedation or confusion. I'd also like to point out that this is not a time where people want to try cannabis for the first time, when they are weak and/or experiencing poor appetite and higher risk of falls. This is not the best time to be trying cannabis or cannabinoids without clear guidance from the clinical care team.

Greg Guthrie: Do you find in writing this guideline and through your clinical experience that most people who are asking about cannabis and cannabinoids, that they already have been trying to use it or are considering it? Because there's a difference there, right? What goal are they looking for, and do they already have a predetermined assumption about what's going to happen with these?

Dr. Eric Roeland: You know, Greg, as clinicians, we talk about a lot of hard stuff. We talk about challenges in terms of health care, access to care, cultural differences, financial toxicity. And it's so fascinating to me that we don't talk about something as simple as whether or not patients are using cannabis. And the reality is that when patients actually bring it up in clinic, I would say that most times they're already using it and are just simply asking for some advice on how to use it safely and effectively. So once I decided to lean in on this topic and create a space for patients and their loved ones to bring it up in clinic, I have found that it's brought up during most clinical encounters.

Greg Guthrie: Fascinating. And so that's likely why the first recommendation of this guideline addresses the importance of communication between doctors and patients on this topic, correct?

Dr. Eric Roeland: Yes, absolutely. I think that doctors are reticent to talk about this topic because of concerns around legal issues, which can be highly varied across the country. And Dr. Braun can speak to this more.

Dr. Ilana Braun: Yeah, so in order to offer the very best care possible, I think that medical teams should know about all the medicines and supplements a person is taking. And this includes cannabis and cannabinoid products. Why? Well, because, as Dr. Roeland mentioned, cannabis and cannabinoids can sometimes decrease the effectiveness of some therapies that a person is on, likely including some cancer treatments, and they can also worsen side effects of other therapies. And then at the same time, cannabis and cannabinoids can be helpful in managing some symptoms of cancer and side effects of cancer treatment. So using them involves a careful weighing of risks and benefits.

So for these reasons, oncology teams really do want to be part of the conversation as someone thinks through d