Cancer Topics – Medicinal Cannabis

How do you talk to patients about medicinal cannabis? Dr. Ashley Glode (University of Colorado) moderates a discussion on effectiveness and safety, misconceptions and more. Featuring Drs. Ilana Braun (Dana-Farber Cancer Institute), Daniel Bowles (University of Colorado), and Kent Hutchison (University of Colorado). Subscribe: Apple Podcasts, Google Podcasts | Additional resources: education.asco.org | Contact Us Air Date: 1/19/22   TRANSCRIPT ASHLEY GLODE: Hello, and welcome to ASCO Education's podcast on medical cannabis, also referred to as medical marijuana. My name is Ashley Glode, and I am an associate professor with the University of Colorado School of Pharmacy. It's my pleasure to introduce our three guest speakers Dr. Ilana Braun is chief of the division of adult psychosocial oncology at Dana-Farber Cancer Institute, and an assistant professor of psychiatry at Harvard Medical School. Dr. Daniel Bowles is an associate professor of Medical Oncology at the University of Colorado. We're also joined by Dr. Kent Hutchison, a professor of psychology and neuroscience at the University of Colorado Institute of Cognitive Science. Let's start with a simple but fundamental question. What is medical cannabis or medical marijuana? ILANA BRAUN: So Ashley, I think that's such a great first question. I think of medicinal cannabis as herbal nonpharmaceutical cannabis products that patients use for medicinal purposes. And typically they're recommended by a physician in compliance with state law. DANIEL BOWLES: Dr. Braun makes a really good point. And I think it's important to know when patients are referring to medical cannabis, there's a wide variety of different things they could be referring to. Sometimes they would be referring to smoked herbal products, but there are also edibles, tinctures, ointments, creams, all sorts of herbal-based products that people use and call medical cannabis. And then there are also the components that make up medical cannabis-- largely, the cannabinoids. And I think the big ones people think about are THC and CBD. And sometimes those are used in their own special way. So I think that it's important for us as providers to be able to ask our patients, what is it that you mean when you say, I'm using medical cannabis? ILANA BRAUN: I think that's such a great point. And I will add I think it's also important to remember that when you offer a medicinal cannabis card to a patient, you're giving them license in most states to access any number of products. It's not an insurmountable challenge, but it's a whole new world for traditional prescribers who are used to writing a prescription and defining what is the active ingredient, how often a patient will take the medicine, by what means. DANIEL BOWLES: I think the other thing we need to be very aware of, as hopefully people are listening to this across the country and elsewhere, is the laws vary wildly from jurisdiction to jurisdiction about what consists of medical cannabis, who is allowed to use it, and in what quantities. So I think it's really important that as we learn about these and we think about these, we think about how they apply to any of our specific situations in which we live in practice. KENT HUTCHISON: So it's interesting-- just follow up on what Dr. Braun and Dr. Bowles, what they're saying, those two words-- right-- medical and cannabis. I think the medical part is somewhat easier because it can refer to the reason the person is using. Are they using for medical reasons are they using for recreational reasons, even though that's a blur? But the cannabis part I think is what's really complicated. And this is what Dan was getting at. All the different products, all the different cannabinoids, I mean all the different bioactive terpenes and everything else in the material, all different forms of administration. That is where it gets super complicated to really define what that is. And then of course, there's so little research we don't really know what all those constituents do. ASHLEY GLODE: Now that we kind of have a little bit of familiarity with medical cannabis, can you comment on adult use cannabis and what that might mean for a patient? ILANA BRAUN: Ashley, I think it's a really good question. And in some of the early research I did to try to understand where medicinal ended and adult use began, or adult use ended and medicinal began, I began to discover a theme that emerged, which is they sort of blend into each other often. In other words, some of the oncologists that I spoke to believed that it was not such a bad thing for a patient with serious illness, and pain, and many other symptoms to have a sense of high or well-being. And conversely, when I spoke to patients using cannabis, sometimes a cancer patient used medicinal cannabis for enjoyment, and sometimes they used it for symptom management, and sometimes they used it for both. And so I think it is somewhat of a slippery slope between the two. Would you agree? DANIEL BOWLES: I think there are definitely blurred lines between the two. I think that the advantages of what most states would recognize as medicinal cannabis is usually they're less expensive, patients can use them in larger quantities. There are certain advantages. But there's also paperwork that goes along with medicinal cannabis that some patients don't feel comfortable with. Or particularly I think when you have a patient who's interested in trying cannabis or a cannabinoid for the first time, they might not want to go through all the extra steps required getting that medical marijuana card, whereas adult use, I think people feel more comfortable, at least in my state, sometimes walking into a dispensary to discuss the options with people who work at the dispensary and then get it from more of an adult use or recreational cannabis initially. And then if that's something that they find helpful for their symptom management, to then take those extra steps and try to get a medicinal card. ILANA BRAUN: I agree with Dr. Bowles that the target symptoms or the target effect is often similar and access can differ. KENT HUTCHISON: Yeah. Just to chime in, I agree. I agree also. It's definitely-- the lines get blurred. The recreational user might also appreciate-- for example, college students, I hear them say a lot of times that they appreciate some of the anxiety-reducing aspects-- right-- even though they're not necessarily a person who has an anxiety disorder. And then of course, patients appreciate a slight increase in euphoria or positive affect, and what does that mean? Is I mean they're also using for recreational reasons? Or is that completely, I guess, legitimate? On the other hand, there are sometimes I feel like when-- especially on the recreational side-- when people are using for the more psychological effects, the sort of psychotropic effects, I know sometimes the medical patients refer to that as being a little bit loopy as a side effect. So I feel like there's definitely some blurred lines. And maybe there are some places where we can think about in perhaps in a less blurred kind of way. ASHLEY GLODE: How often do you guys have a patient ask you about medical cannabis? And what are the most common questions they might have for you? ILANA BRAUN: In my psycho-oncology practice, patients frequently tell me they're using cannabis, often with good effect and minimal side effects for polysymptom management-- for instance to address nausea, or pain, or poor appetite, or sleep, or mood, or quality of life. But they don't ask me a lot of questions. For instance, one of my longest-standing patients. A man with metastatic cancer and gastroparesis. Vaporizes cannabis before meals to keep his weight up. And many of my patients also use cannabis as cancer-directed therapy. And for these patients, side effects can sometimes be more pronounced. For instance, I have a lovely patient with metastatic cancer who follows a Rick Simpson protocol. So what is that? That's an online recipe marketed with an antineoplastic claim. And so this patient targets hundreds milligrams of cannabinoids daily. And with such high cannabinoid doses, she sometimes feels spicy, or out of it, as she describes it. And then I had another patient who targeted high daily doses and developed a debilitating nausea and vomiting that was initially diagnosed as chemotherapy-induced nausea vomiting because it was so hard to tease out in the setting of so many medicinal agents, what was what. But the symptoms resolved completely within weeks of the cannabinoids being halted. And so as I mentioned, what's notable about all three of these patients, and many of the others I see, is that they are quite open with their oncology teams and me about their medicinal cannabis use. But they don't seem to rely me or other members of their oncology team for their therapeutic advice . We insert ourselves when we see potential harm, but much of the decision-making seems to be made-- I don't know in the naturopath's office, at the dispensary counter, or by trial and error. And this anecdotal experience in my practice is borne out in my research findings as well. Patients are just not getting the bulk of their cannabis therapeutics information from their medical teams. DANIEL BOWLES: In my clinical practice, I am asked about cannabis or cannabinoids a fair, amount often in the context that Dr. Braun is describing, where a patient is coming in and they're already using a cannabinoid or they are planning on doing it and they just want my opinion. And I think unlike talking about more conventional cancer-directed therapies where they really rely, I think, on their medical team for information and guidance, we are often more a supplement I think in terms of information. In terms of the patients who come to ask me about cannabis or let me know that they're using cannabis, it's a very wide selection of people. I see young people, old people talking about it, men, women, a variety of different malignancies. So there really is a lot of usage or are thought about usage of cannabis or cannabinoids amongst our cancer patients. I think if you look at the studies, they'll tell us that depending on where we're working, anywhere between 20% to 60% of patients have used cannabis in the last year to help manage some sort of cancer-related symptoms. And I think the other thing that is notable is you'll find people asking about cannabis or cannabinoids who I think we might not have otherwise expected. So for instance, Just this past week, I had a patient with anaplastic thyroid cancer in his 70s, and his daughter was wondering whether he could try CBD to help with his sleep and anxiety. She wanted to make sure that it wasn't going to interact with this cancer therapies. And I appreciated her bringing it up, and we could have a frank discussion about the pluses and minuses of it, just like we might any other therapeutic intervention. So I think that particularly as the laws have changed across the country, more and more people are willing to tell us that they're trying cannabinoids and cannabis than maybe would have even 10 or 15 years ago. KENT HUTCHISON: I think in an ideal world, patients would be talking a lot more with their physicians about this topic. And I think unfortunately that a lot of people do get their information from dispensaries. From the media, from social media, from their kids, and from whoever. And I think that's something that I hope will change in the future. DANIEL BOWLES: In terms of questions that I'm often asked, I'll be asked if it's going to interact with their cancer treatments, in terms of making their medications more or less effective. I do get questions about how I think their cannabis use might affect some of their symptoms. I get questions about other drug-drug interactions-- let's say, interactions with opiates, or benzodiazepines, or some of these other medications that a lot of our patients are on. ASHLEY GLODE: In a recent survey 80% of medical oncologists who discussed medical cannabis with their patients, 50% recommended it in the past year, but only 30% felt knowledgeable enough to make recommendations. What do you guys think needs to be done to address this knowledge gap? And what resources do clinicians have to get and stay informed? DANIEL BOWLES: So I'm a big fan of the NCI's PDQ as a great resource. It has a fairly objective information about cannabis and cancer specifically. So I think that's a nice reference for people who are interested in getting an initial overview on the topic. I think there are also a number of different educational programs. I know the University of Colorado, for instance, has a Cannabis Science Master's and also a certificate program. So there are courses available for people who want to educate themselves more on this topic. ILANA BRAUN: Yeah. I guess when I think about what needs to be done, I think that cannabis needs to become a routine part of medical training curricula and CME programs. I think that a federal funding for high-quality clinical trials and a loosening of federal restrictions on accessing study drug were to occur, that would be really a big boon for the medical community. And my colleagues on this podcast I know are doing some very creative pragmatic clinical trials naturalistic studying what is happening in the field. And I am doing clinical trials using an FDA-approved version of cannabinoids. But it's still very hard to study whole-plant cannabis in a form that is sort of a standardized trial drug in a cancer patient. And then when I think about where I would begin to read, I don't think there is a single source, unfortunately. But a great place to start reading is actually a project that Dr. Hutchinson was a part of, which was an expert panel that was assembled by the National Institute of Science Engineering and Medicine in 2017. And they produced a monograph on the health effects of cannabis and cannabinoids. And it's several hundred pages long, including sections devoted just to oncology. So in other words, there is scientific evidence to evaluate, and it's sizable. DANIEL BOWLES: The Austrian Center for Cannabinoid Clinical and Research Excellence also is a helpful resource. One of the nice things about that is they actually give some dosing suggestions or ideas for people who really don't quite know where to start. Right now, there aren't a lot of people in that position to say, here's how it should be done. Here's how it gets dosed. Here are the data to support those decisions. And so the folks in the next level of training don't learn it in the same way that we have learned how to prescribe other medications. And they can't then lay it down. So because the data are scant, in some respects, and particularly for herbal products that So. Many of our patients are using, I think it falls outside the medical model that we've all become so used to using to learn how to take care of patients. And I think that's one reason that so many oncology providers feel interested in learning more about this topic, but don't feel comfortable giving patients guidance on how to use them. KENT HUTCHISON: So both Dr. Braun and Dr. Bowles identified some of the key resources out there. And certainly the training issues that Dr. Bowles just talked about are important. And I do want to emphasize the one thing that Dr. Braun mentioned, which is basically that we do-- we lack research and we lack data on some key important issues, like dosing, for example. What dose is effective? So cannabidiol has been out there for a long time, but what dose is effective for what? We don't know, right? So we definitely lack research. And there are definitely obstacles to doing that research. ASHLEY GLODE: So you guys brought up some good points about there being a lack of data, but also there is some evidence. So what is the current research and evidence on the efficacy of medical cannabis for management of cancer symptoms and cancer pain, specifically? DANIEL BOWLES: So there was a really nice review article that just came out in the BMJ looking at cannabis and cannabinoids, not specific to cancer pain, but including cancer pain. And what they found-- they looked at different preparations from herbal products-- smoked herbal products, oral agents-- cannabinoids, more specifically. They found there is a modest, but a real improvement in pain in patients or research subjects treated with cannabinoids versus those usually typically treated with placebo. In particular, the data are supported in neuropathic pain, I'd say more so than the other pains. I think the data are less compelling with regards to many of the other symptoms that people often use cannabinoids for, such as sleep, anxiety, appetite, things along those lines. ILANA BRAUN: So I'll tell you a little bit about how I think about the evidence base in oncology for cannabis use. So I'll preface this with two points. The first is that, as I mentioned, cannabis products tend not to be one active ingredient, but hundreds of active ingredients-- cannabinoids, phenols, terpenes, they all have bioactivity. And they don't work individually, they work through complicated synergistic and inhibitory interactions that have been termed entourage effects. So I don't think one can easily extrapolate from clinical trials of, say, purified THC, to understand whole-plant cannabis' activity in the body and how it might perform in humans. And then the other point I'll make is that when I think about the types of clinical evidence that we as clinicians hold dearest, it's clinical trials of our agent of interest in our population of interest. So cancer patients using whole-plant full-spectrum cannabis that they would access at a dispensary or grow in their own home. With this in mind, I believe the strongest evidence, randomized double-blind placebo controlled trials of whole-plant cannabis and oncology populations begins to support its utility for chemotherapy-induced nausea and vomiting. So there have been a few studies that have looked at this. But just in 2020, the most recent is a study by Grimison, et al. It was a multicenter randomized double-blind placebo controlled crossover trial comparing cannabis extract. And I think the extract they use was a 1 to 1 THC to CBD ratio versus a placebo in patients with refractory chemotherapy-induced nausea and vomiting. And what they found was that with active drug, there was a complete response in 25% of participants versus only 14% with the placebo. And although a third of participants experienced additional side effects with the active drug-- so remember, this was a crossover trial, so they saw both arms-- 80% preferred cannabis to the placebo medication. So that's clinical trials of cannabis and cancer. But if we expand the base of the pyramid of acceptable evidence to include high-quality clinical trials for health conditions other than cancer and extrapolate back, then I agree fully with Dr. Bowles that there's a growing body of evidence that cannabis may be beneficial in pain management. And there have been many clinical trials done in this arena, and they span myriad pain syndromes, including diabetic neuropathy, post-surgical pain, MS pain, sickle cell pain. And so it does seem like cannabis works for pain management in several other illness models, so we could extrapolate back and hope that it works in cancer pain. And then there is a small body of evidence with nabiximols, which is a pharmaceutical that has a 1 to 1 THC to CBD ratio. And it's a sublingual metered dose spray. And it has been trialed for opioid-resistant cancer pain. And this is not as a single agent, but as an adjuvant to opioids. In early trials, two times as many participants in the active arm as compared to the placebo arm demonstrated a 30% pain reduction. And for the pain specialists who are listening, they will know that is a substantial pain reduction. But then, additional studies fail to meet primary endpoints. I think there were three clinical trials that followed. Nabiximols was found to be safe and effective by some secondary measures, but the FDA opted not to approve nabiximols for cancer pain. So I think there's some suggestion of effect, but there's some smoke, but no fire-- no pun intended. DANIEL BOWLES: I think many of the studies that have been done looking at cannabis-- or cannabinoids-- have been compared to placebo or they've been crossover. And I would say fairly consistently, there is some improvement in pain scores with the cannabis products versus placebo kind of across a wide variety of disease spectrums with regards to pain. I think one of the other questions that a lot of people have asked is, can you decrease people's opiate usage using cannabis? As we know, there's a huge epidemic of opiate misuse in the United States of America right now. And I think many people are looking for ways to decrease opiate usage. There was a nice study done from Minnesota in conjunction with the Minnesota dispensaries-- or state marijuana program-- where some researchers randomized people to starting kind of herbal cannabis products early in their study or three months into their study. So it was kind of a built-in control. And they looked at opiate usage rates, pain scores, quality of life scores, et cetera. What they found is there, again, was some improvement in pain control overall in the cannabis users. However, it did not equate to a decrease in opiate usage. So I think that it's an open question that I think a lot of people want to know the answers to before they start recommending or incorporating cannabis or cannabinoids more widely into their practice. KENT HUTCHISON: It's certainly a complicated issue, in some ways, right? Because the research which is summarized very nicely by both Dr. Braun and Dr. Bowles, it is suggested, but not overwhelming, by any stretch, right? It's not clear-cut. And I think that one of the big issues here we talked about the very beginning is how complicated this cannabis thing is. and Dr. Braun alluded to this also, that there are obviously many different formulations, many potentially active constituents in cannabis. And so what has mostly been studied so far is either synthetic versions of THC or nabiximols, which is probably the closest thing to what some people are using. So I think the jury's still out, for sure. And I think hopefully at some point, what will happen is that some of the products that are actually being used by people-- because most people aren't using nabiximols, most people are not using THC only, hopefully there'll be some trials of the things that people are actually using out there in the real world that will tell us something more about whether it's effective or not. And maybe even more specifically, which constituents-- which parts, together are most effective with respect to pain. DANIEL BOWLES: I think one of the other topics that some of my colleagues have alluded to already is not just cannabis' role in symptom management. I think pain is often what people think of, and people are using it for chemo-induced nausea and vomiting, anxiety, sleep, appetite, but a fair number of patients are also using cannabis or cannabinoids with the hopes that it is going to treat their cancer like a chemotherapy or an immunotherapy may. And oftentimes, patients will point to preclinical studies looking at oftentimes very high doses of THC or CBD that might show tumor cell death or tumor reduction in test tubes. And I spent a fair amount of time-- and I know some of my colleagues spent a fair amount of time-- talking with patients about how it's a big step between cannabis or cannabinoids working to slow cancer growth in a test tube, to working in an animal system, to working in people. ASHLEY GLODE: So what are the most important considerations clinicians should keep in mind before recommending medical cannabis to patients with cancer? DANIEL BOWLES: We should be asking why they want to use cannabinoids. I think just like we might any other medication that people are thinking about trying-- or herbal product that people are thinking about trying-- I think we need to ask why they're interested in using these products. So is it for symptom management? Is it for some of the ancillary side effects of cannabinoids or cannabis? Why are they wanting to use it? And I think trying to incorporate that more than into the medical model, I ask my patients, hey, if you're using this particular product, do you feel like it's doing what you intended it for it to do? If it is and it's legal in your state, great. Do it as you feel fit. If it's not meeting your goals, if it's not helping with the pain, or if it's not helping with the anxiety, or it's not helping with the nausea and vomiting, maybe we should rethink whether we would use it. Just as if I was prescribing more conventional anti-nausea medication and you didn't think it was working, we wouldn't keep using it. So I think that's a really important thing to keep in mind. I think the other thing to know from a safety standpoint is, who else is in the household? We have a psychiatrist on the call with us today. I think there is an ample amount of data that cannabis is not safe for young people. It's not safe for growing brains. And I think we need to make sure, just as we would want people's opiates to be secured, that their cannabinoids and cannabis products are secured as well, from those who do not want to use them. ILANA BRAUN: And the thing I would keep in mind is that in most states, giving patients a medicinal cannabis card is allowing them to access any number of products with different ratios of active ingredients, delivery mechanisms, onset of action, potencies. And if you don't discuss all of these issues with your patients, these are things that they will decide at the dispensary counter, or by discussing with friends and family, or by trial and error. And I think it's really important that we clinicians guide this narrative. ASHLEY GLODE: So what kinds of patients are not good candidates for medical cannabis? DANIEL BOWLES: I would not recommend medical cannabis for people who can't meet some of the criteria we already discussed. So people who can't keep it safe in their households or have concerns about diversion in their own households. Those are people who I think would not be great candidates for medicinal cannabis or cannabinoids. ILANA BRAUN: As the psychiatrist on the call, I would add that I worry for people with a strong history of psychosis, or currently psychotic, or with a strong family history of psychosis. And perhaps those severely immunocompromised, since there is evidence of fungal and mold contamination in some cannabis products. DANIEL BOWLES: The other group of people I discussed this with are patients on immunotherapies. One of the ways that cannabis may be effective in some of the symptoms we discussed is it's an anti-inflammatory agent. One of the ways it could be detrimental for patients on immunotherapies is that it's an anti-inflammatory agent. There is one small study that suggested that patients might have worse responses to immunotherapy who are cannabis users versus those who are not. So that is a conversation I like to have, just so patients feel like they can be informed. I think lastly, cannabis even for people with medical cards, is not free. So there can be a financial burden for people who are using it. So that's something that I'll often bring up with people as well. KENT HUTCHISON: One thing I would add to this would be history of a substance use disorder might also be a consideration here as well. Mainly because you don't know what the person is going to get, and it could be something that lends itself to relapse or encourages a problem. So I would add that to list. ILANA BRAUN: And I would second what Dr. Bowles said about the financial challenges of using cannabis regularly medicinally. It's not something that's covered by insurance, either. So these are out-of-pocket expenses, and they can add up fast, particularly for patients in the oncology space using it for antineoplastic therapy. ASHLEY GLODE: So is there a concern about drug-drug interactions for patients currently undergoing active cancer treatment? DANIEL BOWLES: There are some data that there can be drug-drug interactions with cannabis and certain agents. In particular, cannabidiol, or CBD, is a CYP3A4 inhibitor. And there are a lot of drugs that are metabolized through that particular system. So I think that that's the clinical relevance of those interactions, I think, is sometimes unknown. But that is another topic that I do think we need to make sure we bring up with our patients. ASHLEY GLODE: Thank you. Yeah. So a lot of what we'll do is from a drug interaction perspective, use the FDA-approved products that we have available to run through a drug interaction checker, like Dr. Bowles mentioned. So we'll use dronabinol as the THC-based product and epidiolex as the CBD-based product. There's also some resources, such as natural Medicines Database. And some of the pharmacy programs that we use, you can actually put in marijuana or cannabis as a drug and run drug interaction checks. So there's multiple potential interactions, like he mentioned, through the immune system. But through the cytochrome P450 pathway, cannabis has been shown in some instances to be an inhibitor, sometimes an inducer of certain enzymes, as well as a substrate. So it's really important to work with your pharmacy colleagues to run through different potential interactions that may be present. ILANA BRAUN: I'll just add one thing, just in case that's helpful. I mentioned earlier in the episode that I had a patient who used cannabis as an antineoplastic drug, and targeted very high doses and developed a terrible nausea and vomiting. And when she stopped, so did the nausea and vomiting, even though her chemotherapeutic continued. And I, to this day, don't know if that was a cyclic nausea and vomiting syndrome, which has been known to plague some heavy cannabis users, or whether drug-drug interactions led to her high-dose cannabis triggering high blood concentrations of her cancer-directed therapy at the time. And so I think that drug-drug interactions do need to be carefully weighed. ASHLEY GLODE: So wrapping up, has the medical community stance on medical marijuana shifted in recent years with legalization in many states? ILANA BRAUN: I don't think we know the answer to this, about how sentiment has shifted because there aren't longitudinal studies that I know of examining this question. But we need some. And one could imagine that as medicinal cannabis becomes are commonplace, providers are increasingly confronted with questions about how to guide care and the desire for high-quality clinical trials and in-depth cannabis therapeutics trainings increases-- and as one piece of evidence for this, at the end of 2020 the National Cancer Institute held a first-in-kind four-day conference at the intersection of cannabis and cancer. And so I'm hopeful that grant opportunities will follow from that. DANIEL BOWLES: I think overall there has been more willingness to discuss cannabis in the context of patient care in the last decade. A couple of ways that I see this is I much more frequently see cannabis use described not necessarily in the drug history, or in the social history, but in the medical history, or in their medications, if they're using it for medical or therapeutic purposes. I think the other place that I've noticed cannabis usage become a bit more mainstream is in the clinical trial setting-- not in clinical trials of cannabis, but one of the things that many of us do is clinical trials of new drugs. And very frequently, 10 years ago we ran into trouble trying to get our patients who were using cannabis products for cancer symptom control onto these clinical trials because of potential drug-drug interactions, or just the fear of the unknown. And I feel like we run into that less commonly now. KENT HUTCHISON: I think it's also worth pointing out that there have been more and more podcasts like this one, right? So to the credit of this organization, I think we are seeing some change. I just wanted to highlight that. And I compliment everyone here for putting us together and putting it out there. ASHLEY GLODE: All right. Well, thank you. That is all we have for today. And thank you very much Drs. Braun, Bowles, and Hutchison for a delightful conversation. Thank you so much to all the listeners tuning into this episode of the ASCO Education Podcast. [MUSIC PLAYING]   SPEAKER: Thank you for listening to this week's episode to make us part of your weekly routine, click Subscribe. Let us know what you think by leaving a review. For more information, visit elearning.asco.org. 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. 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