What role can medical cannabis play in a breast cancer treatment plan and why are doctors still hesitant to advocate for it?
Results of a growing number of studies (1) indicate that cannabis is used by breast cancer patients for the treatment of the symptoms of their cancer, such as nausea due to chemotherapy. But can it do more than that?
The jury is still out about how or even if cannabis can actually help reduce the growth of cancer cells or otherwise impede the advancement of the any kind of cancer. However, there have been intriguing developments.
Despite this, mainstream breast cancer doctors, working on treatments for one of the more successfully treatable types of cancers, are watching these developments carefully. More and more of them face decisions about recommending cannabis (either tetrahydrocannabinol [THC] and cannabidiol [CBD] or CBD only) based solely on anecdotal evidence or restricted research (2), as they are seeing their patients successfully manage their own care using cannabis.
But patients handling their own care is somewhat antithetical to what doctors have been trained to do. Doctors want to be more involved in anything that helps their patients have a better quality of life.
There are new applications of cannabis for treating breast cancer in Israel, where the use of the cannabis plant for the palliative treatment of cancer patients has been legalized in multiple jurisdictions (3).
Last May, breast cancer advocacy organization, Breastcancer.org, released findings from a survey of breast cancer patients evaluating medical cannabis use to manage symptoms related to breast cancer at the 2020 American Society of Clinical Oncology’s (ASCO) Annual Meeting (4).
Actual clinical trial support for the use of medical marijuana to manage symptoms is scarce, according to the Breastcancer.org survey. But many known effects of marijuana are appealing to cancer patients hoping to alleviate symptoms of treatment. Meanwhile, medical science urges caution.
Respondents to the survey often reported using medical cannabis to manage more than one symptom or side effect, the most common of which included pain (78%), insomnia (70%), and anxiety (57%). The survey concluded (4): “It’s extremely important to know that cannabis is not a cure or treatment for breast cancer, despite many claims. It’s dangerous to use cannabis instead of proven cancer therapies.”
Only one clinical trial (5) has ever been published on the effects of Delta-9-THC on cancer growth in humans. Doctors administered oral Delta-9-THC to nine patients who experienced tumor progression despite surgical therapy and radiation treatments. The major finding of the study was that Delta-9-THC was safe and did not cause any obvious psychoactive effects in a clinical setting.
Another study in 2009 (6) found that cannabinoids have elicited anti-cancer effects in many different in vitro and in vivo models of cancer. “While the various cannabinoids have been examined in a variety of cancer models, recent studies have focused on the role of cannabinoid receptor agonists (both CB1 and CB2) in the treatment of estrogen receptor-negative breast cancer,” as reported in the study (6).
Advocates for using cannabis for breast cancer treatment, such as Breastcancer.org or Americans for Safe Access (ASA), try to assuage the fears that licensed medical practitioners face when their patients ask for their advice on medical use of cannabis.
It’s still a Schedule I substance, making it as bad as heroin in the eyes of the U.S. Drug Enforcement Administration. Discussing cannabis with patients suffering from breast cancer is one thing—prescribing it is a clear violation of the law.
According to the ASA, medical professionals have a legal right to recommend cannabis as a treatment in any state, as protected by the First Amendment. That was established by a 2004 United States Supreme Court decision to uphold earlier federal court rulings that doctors and their patients have a fundamental constitutional right to freely discuss treatment options. “Under federal law, cannabis may not be prescribed, but its therapeutic use can be recommended without any legal jeopardy,” the ASA states (7).
The court ruling that protects medical professionals comes from a lawsuit brought by a group of doctors and patients led by AIDS specialist Dr. Marcus Conant. The suit was filed in response to federal officials who, within weeks of the legalization of medical cannabis in 1996 in California, threatened to revoke the prescribing privileges of any physicians who recommended cannabis to their patients for medical use. Conant contended that such a policy would violate the First Amendment, and the federal courts agreed (8). In that case (Conant v. Walters ) the Ninth Circuit Court of Appeals held that the federal government could neither punish nor threaten a doctor merely for recommending the use of cannabis to a patient. “But it remains illegal for a doctor to 'aid and abet' a patient in obtaining cannabis,” according to court documents.
While it appears that doctors can legally discuss cannabis with their cancer patients in states where medical cannabis has been legalized, there are still concerns about how such phrases as “aid and abet” might be interpreted.
Before that ruling, doctors had their hands tied when it came to discussing cannabis with their patients. One example: Dr. Milton N. Estes, associate clinical professor in the Department of Obstetrics, Gynecology and Reproductive Medicine at the University of California-San Francisco (UCSF), reported his feelings as a result of the government’s public threats (8): “I do not feel comfortable even discussing the subject of medical marijuana with my patients. I feel vulnerable to federal sanctions that could strip me of my license to prescribe the treatments my patients depend upon, or even land me behind bars. . . . Because of these fears, the discourse about medical marijuana has all but ceased at my medical office. . . . My patients bear the brunt of this loss in communication.”
Nearly every story about a breast cancer patient getting access to cannabis treatment follows a sort of four-part narrative: dealing with the adverse effects of prescribed pharmaceuticals for treatment; asking their doctor for a better way of dealing with side effects from the cancer drug therapy; hearing about the benefits of cannabis from other cancer patients; then trying cannabis and experiencing better, drug-free relief—all as their doctor approves by not tacitly disapproving of their use of cannabis. That is, if the cancer patient even discloses their cannabis use.
Dr. Danielle Noreika is the medical director of palliative services and an associate professor of medicine in Virginia Commonwealth University’s (VCU) Division of Hematology, Oncology and Palliative Care. She works with other doctors in the VCU Massey Cancer Center, which is one of only two cancer centers in Virginia designated by National Cancer Institute, and one of only 71 cancer centers in the United States.
Virginia legalized medical marijuana in July 2020 (9), one of the more recent states to do so. Doctors in Virginia can recommend cannabis and issue written certifications, but not prescriptions.
Dr. Noreika is one of 24 medical marijuana licensing doctors in the Richmond, Virginia area (10). As much as she appears to be an advocate for cannabis, she is careful in her explanation about what that means. “I will say in general, as a way of not directly answering that question about being an advocate, is that I’m an advocate for things that are going to improve the quality of life of my patients,” Dr. Noreika said. “Because I think we still need to know more for me to say that I know exactly where this fits into the treatment plans for my patients at this point.”
She added that she is very open to seeing more research done over time, where cannabis could be integrated into patient care. “Absolutely. I am always wanting to see something else that we can kind of add to what we do that will make patient’s lives better,” she said.
“As far as the health care institutions and my talking to colleagues about marijuana—not only here, but also in other places—there’s still a lot discussion about not knowing how to integrate (cannabis therapy), and they are not sure what to do with it. They say that they are just going to watch it for awhile,” said Dr. Noreika. “Our practice in the state at the moment is that the Board of Pharmacy has to sort of agree that you’re not prescribing it, but you’re sort of writing a certification for a patient to use. And you have to be registered for that. I think there’s patients who may benefit from cannabis therapy. But in real life, at this point, we haven’t gotten to a place where we’re able to see kind of an uptake on that, at least sort of globally, in a lot of the different institutions.”
Until there is more evidence to go on, it’s hard to tell any individual patient about the benefits and side effects. “There’s always both whenever you’re considering any sort of substance,” Dr. Noreika said.
The other challenge for patients right now, she said, is when patients have an interest in pursuing cannabis treatment, but find out that many providers are not listed with the state yet. “There’s this sort of thinking that ‘OK, if this is really what I want for my care, I have to sort of go out and find the providers that are willing to kind of make this certification.’ But there’s not as many of them right now. And many of them are not able to accommodate new patients.”
In sharp contrast to Virginia, Colorado legalized medical marijuana more than 10 years ago (11). Dr. Virginia Borges, medical oncology professor at the University of Colorado School of Medicine, said that medical cannabis is something that she has had a fair amount of experience with by virtue of how her patients choose to support themselves during their cancer care. “So it kind of behooved me to get as educated as I could, based on the data that I’ve been able to find or others have been able to help find for me, or in the field,” Dr. Borges said. “My viewpoint is that cannabinoid containing products are useful as a supportive care measure in cancer treatment, not as a direct cancer targeted therapy, because we don’t have data for that in the clinical setting at this point in time.”
There is some interesting preclinical evidence about the effectiveness of cannabis for real anti-cancer treatment. “But the problem is that there’s a lot of things that look interesting when they’re in the lab,” Dr. Borges said. “But whether that would ever pass muster and get to the level of a clinical trial where we could prove that it could be an actual therapy, an anti-cancer directed therapy, we’re just not there yet.”
Dr. Borges said that some of the work being done in oncology is evidence-based, where there have been randomized clinical trials done. “Some of that is practical evidence gained over time by virtue of either what our patients choose to do, or just what we gain experience with,” she said.
“I think products that contain CBD, whether that’s a cannabis product that also has THC where one of my patients would have to go to a dispensary to get it, or it’s a pure CBD-containing product that they can get at the grocery store or online, I’ve personally seen it benefit a fair number of my patients in terms of things ranging from insomnia, hot flashes, body aches, symptoms related to some of the endocrine therapies that we ask patients to take,” she said. “And then, for our patients who are struggling with more advanced stages of cancer and more end of life issues, the comfort and anxiety control and relief that CBD containing products can offer is also, I think, apparent in the practical evidence that we’ve gained over time.”
Patients have to choose their CBD products carefully from the many offerings out there that may not be reliable, or that have been contaminated by bad processing chemicals. “It’s like anything else in the supplement industry,” Dr. Borges said. “I view cannabis as a part of the supplement industry. So let the buyer beware.”
CBD has just been another plant-based supplement available to her patients for a long time, she added. “I wouldn’t say that I’m an advocate, as opposed to I’ve seen it benefit my patients, so I recommend it to them, just like I would recommend grape seed extract (12) or other things that we know can offer them benefit as they struggle with their side effects.”
What is most important to her is that she wants her patients to be on endocrine therapy, because some of those drugs reduce the risk of ever developing a recurrence or metastasis of their breast cancer by 50–75%. “So these are crucial drugs for somebody’s wellness after a breast cancer diagnosis. They have to be on these drugs for five years, and they’re not easy to take,” Dr. Borges said.
There are prescription drugs that can be used to help patients with side effects of the endocrine therapy, but Dr. Borges said very few patients are readily accepting of using a prescription drug. “Some of these breast cancer patients are 30 year old women and they don’t want to be taking drugs to manage the side effects of the drug that’s going to have side effects. So, if we can have a more patient-facing, lower risk alignment with how they prefer to manage their care, which also helps me keep them on the endocrine therapy that I know is crucial for reducing the risk of ever having a more advanced stage of breast cancer, it’s kind of a win-win,” she said.
Colorado offers benefits to breast cancer patients by the sheer volume of dispensaries across that state. “A patient can’t literally drive down the street without seeing a dispensary, so it’s pretty accessible,” said Dr. Borges. “CBD is going to handle five of their side effects, like appetite stimulations, which is a big deal in many patients. So a compound that’s going to fix five different things would be where I would choose to leave my recommendation, because they’ll try it, and they’ll benefit from it.”
She added that she thinks the most important thing for her work with patients is to have an open conversation about what is important to them in co-managing their care. “There is a control issue. You have to give patients authority and control over a part of their care and help them understand what’s going to be safe and not safe for them to engage in,” Dr. Borges said. “They are very much looking to try and take some control back after a cancer diagnosis that has really removed a tremendous amount of the control that most of us take for granted in our day to day lives.”
Dr. Noreika said that she, like everyone else, is hopeful that there are substances out there that “on the whole, do have their burdens,” but are potentially safe for individual patients in certain circumstances. “How amazing would it be if it also improves that underlying reason about how your cancer acts,” Dr. Noreika said. “I think I have all the hope in the world. We’re always looking for things that are going to improve the quality of life for our patients.
“We do want to be careful that we don’t get too hopeful because we want to be clear-eyed about what we’re seeing, and make sure we don’t jump on a bandwagon that’s later going to be identified that caused harm or more burden to our patients,” Dr. Noreika said. “I’m looking forward in the future to kind of see more of the research, potentially having it be more easily accessible, and, in practice, to see where it might fit into the patient’s treatment profile.”
As legalization efforts continue to have their impact, perhaps a sort of “mathematization” Internet of Everything (IoE ) systems-based approach to biology will help devise better therapies using plant-based substances such as cannabis and help science understand more about how it works for breast cancer patients.
This transformation of biology, this new understanding of how cells work inside the human body, has already begun and will help maximize the benefits of drug therapy and minimize the side effects. Medical science can go from in vitro (doing tests with cells in a dish or molecules in a test tube) and in vivo (doing tests with cells in living things) to in silico biomedicine (using a computer with advanced models for simulations to test theories faster and more efficiently) (14).
(14) A. Steele, “Ageless – The New Science of Getting Older Without Getting Old,” page 232 (2020) https://andrewsteele.co.uk/ageless/.