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Madeline Colli is the Associate Editor for Cannabis Patient Care and Cannabis Science and Technology magazines at MJH Life Sciences.

Can you tell us a little bit about yourself? How did you become interested in the cannabis industry?

 I’m a clinical research scientist and earned my PhD in clinical psychology from the State University of New York at Buffalo. My early career interests focused on the study of nicotine and tobacco with an emphasis on pharmacological treatments for smoking cessation. As a degree requirement, I completed an internship at a Veterans Affairs facility in Bedford, Massachusetts. As an intern specializing in drug addiction, I would overhear veterans talking about the use of medical cannabis as an alternative treatment for symptoms of post-traumatic stress disorder (PTSD) and as a potential approach to reduce daily use of numerous prescription medications, and that piqued my curiosity.

I was lucky to have the privilege of completing a research postdoctoral fellowship at Johns Hopkins University School of Medicine (JHU) under the mentorship of Dr. Ryan Vandrey, an internationally-recognized scientist in the field of cannabinoid research. There, I worked on several cannabis studies, which cemented my career path choice.

 is a 501c3 nonprofit organization with three central goals: research, education, and advocacy. Through research, we gain valuable insights on the real-world use of and health effects of medicinal cannabis and hemp through our 

. Realm of Caring seeks to educate consumers and healthcare professionals on existing research investigating medicinal cannabis and cannabinoid therapies. RoC’s Care Specialists assist clients worldwide in choosing quality products and provide compassionate one-on-one support to individuals utilizing cannabinoid therapies.

 I became involved with Realm of Caring while completing a research postdoctoral fellowship at JHU under the mentorship of Dr. Vandrey. I helped develop, program, and launch the ORR survey study during my training at JHU.

What do you expect your role as the RoC’s first-ever Research Director to entail (what are your goals)?

 My immediate goals are to increase enrollment in the ORR survey study to improve our understanding of the wide range of medicinal cannabinoids used by individuals with myriad health conditions and symptoms. I will also oversee our ORR survey data and work with our colleagues to publish our findings in peer-reviewed journals. Additionally, I will be regularly updating the Realm of Caring staff on the latest advances in cannabis science to inform interactions with patients, healthcare providers, and the community.

Does RoC offer educational/medical resources for patients and others seeking to learn more about medical cannabis?

Yes! We offer direct support to clients requesting more information about cannabinoid therapy. Resources include: 1) adult, pediatric, and pet dosing guidelines informed by client data and published research; 2) product recommendations; 3) monthly webinars covering a range of topics; and 4) informational blogs updated weekly. Our care team offers free one-on-one ongoing support to clients. Our goal is to provide clients with up-to-date information on cannabinoid therapies and to educate on how to navigate the rapidly growing list of cannabinoid products.

What is the Observational Research Registry (ORR)?

 The Observational Research Registry (ORR) is an online survey study of cannabinoid therapy that examines the health outcomes over time among individuals enrolled in the registry. Following standard research practices, this study has been reviewed and approved by the JHU Institutional Review Board. We strive to make the ORR inclusive; individuals interested in participating are not required to be current medicinal cannabis users nor are they required to have a health condition or a formal medical diagnosis. Participants receive a unique link to the web survey that contains questions that ask about cannabis or hemp product use, prescription and over-the-counter medications, and general health questions that ask about anxiety, depression, chronic pain, sleep, quality of life, and use of health care services. Cannabis legislation reform and emergence of new products opens doors for pursuing future research with widespread implications.

Can you tell us about some of your findings from the epilepsy and cannabidiol (CBD) study you recently published in Epilepsy & Behavior (1)? How did the study come about?

We looked at the use of artisanal CBD, which are non-pharmaceutical products. Compared with Controls (non-users), Artisanal CBD users reported greater health satisfaction, and quality of life ratings that were qualitatively higher (but fell short of reaching statistical significance). Artisanal CBD users also reported lower anxiety and depression compared with Controls, and adult CBD users reported improved sleep whereas child users demonstrated a marginally significant improvement on sleep ratings. Artisanal CBD users also had lower odds of past-month emergency department visits and past-month sick days from school or work. Interestingly, a subset of Controls that denied use of artisanal CBD at baseline-initiated use of artisanal CBD during follow-up surveys; CBD initiators reported improvements in quality of life, physical health and psychological health, and reductions in anxiety and depression. We failed to observe differences between Artisanal CBD users and Controls for past-month generalized or other seizure types. However, our inability to find a difference between Artisanal CBD users and Controls may be attributed to multiple factors. Nearly half of participants (49%) reported no past-month generalized seizures and 40% reported no past-month non-generalized seizure types, which may have resulted in a “floor effect.” Participants also reported a median CBD dose of 1.4 mg/kg/day, which is below the recommended pharmaceutical CBD dose of 10 mg/kg/day.

That study brought together researchers from a variety of locations—RoC, Johns Hopkins University School of Medicine, University of Buffalo, Medical University of South Carolina, and Canopy Growth (1). What role did each of you play in the study?

Heather Jackson, the founder of Realm of Caring, played an instrumental role in conceptualizing this observational patient research study. After multiple conversations with Dr. Ryan Vandrey at Johns Hopkins University School of Medicine and Dr. Marcel Bonn-Miller at Canopy Growth Corporation, the details of the study were finalized, and the web survey was programmed. Following its launch in 2016, we actively monitored study progress and the staff at Realm of Caring assisted with recruitment efforts. After accruing data for several years, Dr. Justin C. Strickland took the lead on writing up the study and all co-authors reviewed drafts of the manuscript and provided critical feedback to publish a high-quality study.

What conclusions did your study unveil? Were you surprised by any of the results?

 Users of artisanal CBD products reported greater health satisfaction, lower anxiety and depression, sleep improvements among adult users, lower odds of past-month emergency department visits, and past-month sick days from school or work. The majority of artisanal CBD users denied the presence of any adverse effects. Longitudinally, Controls that initiated use at follow-up assessments exhibited significant quality of life improvements and significant reductions in both anxiety and depression. No significant group differences emerged for past-month generalized and past-month non-generalized seizure types. This finding was particularly surprising, but review of the data suggests that the combination of a floor effect relative to the percentage of past-month generalized (49%) and non-generalized (41%) seizures may have contributed to this outcome. Looking at individual dosing for artisanal CBD products also revealed a median CBD dose of 1.4 mg/kg/day, which is well short of the recommended dosing for pharmaceutical CBD (10 mg/kg/day).

What are your plans moving forward from the research obtained in your study?

The process of developing and collecting data for our Observational Research Registry (ORR) study highlighted a number of areas for future research. Compared to clinical trial settings, observational studies face a number of challenges due to the absence of a controlled environment. Precise measurement of dosing amount, dosing frequency, and accurate chemotype classification can be influenced by a variety of factors that are beyond the control of the investigators. Identifying, developing, and evaluating novel methodological approaches to help ensure proper reporting is one topic of particular interest to us. Integrating artisanal CBD into a treatment regimen may also be a challenging process; provider knowledge and patient-provider interactions may be most productive when both provider, and patients have open dialogues when considering use of medicinal cannabinoids.

Is there anything further you would like to add?

https://realmofcaring.org/observational-research-registry/

 to participate in our Observational Research Study and to stay up-to-date with our latest research publications, including a study that examined the health effects of medicinal cannabis on anxiety and depression. Register as a client at 

https://realmofcaring.org/resources/client-portal/

 to access our education series and view additional cannabinoid therapy resources.

Articles

Realm of Caring is a 501c3 nonprofit organization that conducts their own research such as their endeavor of the Observational Research Registry (ORR) study. They are also involved in advocacy work to help battle the stigma surrounding cannabis. In this interview, Nicolas Schlienz, PhD, Research Director at Realm of Caring, discusses the organization’s efforts to educate the public and healthcare professionals on the research being done on medical cannabis.

Research, Advocacy, and Education: Realm of Caring Helps Assist in Medical Cannabis’s Growth in the Industry

Talking with Your Doctor About Medical Cannabis and Breast Cancer

Overview of Research on Cannabis for Breast Cancer

Cannabis for Cancer: The Fight to Get Mainstream Medicine Onboard

Taking Matters into Her Own Hands: A Nurse’s Journey to Self-Educate on Medical Cannabis Benefits and Risks

On the Other Side of the Nurse’s Station: A Nurse Turned Medical Cannabis Patient

Breast Cancer Doctors See the Value of Cannabis for Treatment—But Stop Short of Advocating for it

View our interactive October/November 2021 digital edition.

October/November 2021 Digital Edition

Marisa Weiss, M.D., is the founder and chief medical officer of 

, a leading online resource for expert medical and personal information on breast health and breast cancer. With more than 35 years of active practice in the Philadelphia region, Dr. Weiss currently practices at Lankenau Medical Center, part of Main Line Health, a five-hospital health system in the suburbs of Philadelphia, where she serves as director of breast radiation oncology and director of breast health outreach.

Patients have been utilizing medical cannabis for many years to manage symptoms, side effects of treatment, and other mental health challenges that often come along with the diagnosis of cancer. In fact, one of the most widely studied therapeutic applications for cannabis is in the treatment of nausea and vomiting associated with cancer chemotherapy. Yet for many patients, talking with their healthcare providers for the first time about utilizing cannabis in their treatment regimen can feel intimidating and scary.

Healthcare providers are accustomed to patients bringing ideas to them about treatment options and preferences, and cannabis therapeutics should be no different. Just like traditional medications, cannabis can interact with other medications and treatments, so it is important to make sure that your provider has the full picture and can monitor your progress or make adjustments if needed.

We sat down with the founder and chief medical officer of 

, Dr. Marisa Weiss, to get some tips and talking points to help patients start this conversation about the therapeutic use of cannabis for breast cancer. Dr. Weiss shares how cannabis can be utilized for symptom management before, during, and after breast cancer treatment, why cannabis can be a complicated topic for doctors to discuss with their patients, and why it is important for patients to advocate for themselves.

How did you first start hearing about cannabis use for symptom and side effect relief from breast cancer?

 From my patients. So, it never came from any medical source. It was patient after patient asking about it. And initially, I would say ‘You know, that’s a really good question, you need to talk to an expert about it’ and I would encourage them to find somebody who could answer their questions. A few of them came back and said, ‘I’m still interested in that subject but couldn’t find any experts in that arena of cannabis for the management of quality of life, symptoms, etc., for people with breast cancer. Then a specific patient of mine came back and said: ‘That’s not a good enough answer, you really need to get more knowledgeable about this. You’re a leader in the field of patient centric care through 

 and you really need to become a leader in this arena.’ And I said: ‘Well, you’re right!’

These patients were really suffering from symptoms and nothing else seemed to help them. Patients have to go through their state medical cannabis program in which they have to pay out of pocket for the cost of the doctor visit, certification, and all products, paid for in cash without the help of insurance. So it was clear that this was an important enough issue for which people were saying ‘I’ll use my precious personal funds to pay for it,’ which is not really fair if people have to pay out of pocket for something that is helping them from a medical point of view and is not covered by insurance. So, right now it is only an available option for those people who are privileged enough to be able to access and afford it.

What did you do to help educate yourself about the therapeutic use of cannabis for patients with breast cancer?

 I first did the course work that’s required to certify a medical cannabis patient in the state of Pennsylvania and then the state of New York. But that’s only a four hour course that’s required, so it’s not enough knowledge to really be able to understand the potential role that cannabis products may have to solve difficult issues for people going through breast cancer, especially those who are seeking natural remedies or who don’t want to go on pharmaceuticals or who want to avoid narcotics and associated risks. So I did extensive training and started to see patients within my own practice.

 we decided that we needed to know more details about people’s lives: what symptoms they’re suffering from; which of those symptoms are they getting relief through traditional medicines; for which symptoms are they seeking medical cannabis; are they talking to a doctor about their interest or use of medical cannabis; are they using it before, during, or after treatment; what type of products are they using; how many products are they using; what was the source of their products? Breastcancer.org did a national survey of the population going through, about to go through, or have gone through breast cancer. We learned a tremendous amount and we published that data, which reinforced the fact that people were suffering from symptoms which they could not find relief from with other medications.

What did you learn through your survey about which symptoms or side effects breast cancer patients were most able to find relief with or control with the use of medical cannabis?

 The most common symptoms were pain, anxiety, insomnia, and nausea or vomiting. We also found that nearly 80% of cannabis users are using it during treatment. More and more people are using it and understanding its role. More patients are saying it’s helpful with symptomatic management, and noting that nothing else was helpful in the same way.

Is there anything you would caution breast cancer patients about in regards to medical cannabis use?

 There are a lot of claims on the web about cannabis being an anticancer therapy. I would say that the data showing that cannabis can slow the spread of cancer, that’s all based on petri dishes, not people yet. We don’t know if there is any basis for that from a scientific perspective. So, I would stick with traditional proven therapies, because we don’t know if it’s safe or effective. We don’t know how it will interact with traditional therapies.

Do you ever suggest cannabis to patients who don’t ask about it specifically?

 Definitely. Breast cancer and most of these cancers affect women who are typically in charge of the family and who are usually very risk averse. They don’t want to get into trouble.

Women are looking for solutions, not looking to get high. They’re looking for ways to live their life the way they want to. With symptoms like pain, anxiety, and nausea or vomiting, they aren’t going to be able to function in these crazy busy lives that they have where they’re not just taking care of themselves but also their families, they’re working, they’re involved in the community.

When I hear about a problem that stands as a barrier to living their best quality of life then I’ll say: ‘Well what have you been doing to improve that?’ Many patients will say they’re afraid of pharmaceuticals, and afraid of dependence. They want natural remedies, not drugs that can make them feel intoxicated. So that’s a natural way to ask if they’ve considered medical cannabis. It’s part of the holistic way we help people recover.

Why are so many healthcare providers apprehensive about talking with their patients about cannabis?

 Most doctors in the breast cancer community are apprehensive for a variety of reasons. First, cannabis is not part of most medical schools’ curriculum, so most doctors are without any formal training. In the absence of insurance, you would need a second track in your practice just to handle it. Another important component is that none of it is integrated into the electronic medical record for patients, so it’s not integrated within a patient’s holistic care within the traditional medical system like pharmaceuticals are. If I were to see somebody and they were to go to a dispensary to get products, the list of products they get from a dispensary are not entered into the database, so you have no idea what types of products your patients are using. That’s an uncomfortable place for a doctor to be in; you qualify someone for a medicine but you don’t know what they’re taking, in many cases they don’t know what they’re taking. They’re not allowed to bring the product on campus to show you what they’re taking because it’s illegal. So there’s a lot of logistical requirements that are deterrents.

Most importantly, even though we have about 34+ states that have legal programs, cannabis is still illegal at the federal level, and many doctors do not feel comfortable talking about products that are illegal. Even when it is legal at the federal level doctors may not be comfortable until there is a scientific research foundation on which to base recommendations. So that is why I’m committed clinically to perform vital foundational research to determine what our needs are, patterns of use, knowledge, attitudes, behaviors, and beliefs to determine the role of cannabis, and to have it based on something scientific.

What would help encourage more healthcare providers to recommend cannabis?

Well the main thing that has to occur is cannabis medicine education in medical schools and the commitment to research. Because we have many individual anecdotes, for centuries, of the individually reported value of products but it has not been collected in a scientific format. So we need better clinical trials to collect data on the effectiveness and the role it plays in the treatment of cancer.

Can you tell us about your chemotherapy-induced peripheral neuropathy (CIPN) study?

I decided to identify a clinical problem that was really awful and common for which medical cannabis seemed to have a unique role. That is in the treatment of patients with chemotherapy-induced peripheral neuropathy (CIPN); symptoms include pain, numbness, as well as pins and needles in the hand from some of the most commonly used chemotherapy. Medications that are commonly used in most cancers but especially breast, colon, colorectal, ovarian, and uterine cancer. The data we had showed that cannabis could play a role in preventing that problem as well as treating that problem. This came from a study on mice that a woman named Dr. Sarah Ward did which showed that if you gave cannabidiol (CBD) from hemp together with chemo that it would reduce the chances of CIPN from chemo. So, I wanted to study that. Not only does CIPN impact quality of life when people have pain in their hands and feet, it hurts fine motor skills like buttoning a shirt or opening a peanut butter jar. It ends up impacting quality of life and survival making people less likely to complete their chemo, meaning their care is compromised.

I decided I was going to do a randomized double blind trial looking at prevention of CIPN with cannabis. So I went to all these researchers and they said: “oh, no, no, no, you’ll never get that through the FDA, you’ll never get that through NIDA, nobody’s done it before.” She told me it’s not gonna happen, just do it as an observational study, which is not a research approach that is going to change anyone’s mind or establish a scientific basis for insurance coverage. The FDA wouldn’t let me do it together with chemo because they said: ‘We don’t know what’s going to happen when you give both at the same time. There may be a drug-drug interaction where the chemo won’t work as well and we can’t do that until chemo is over." So basically I started a randomized double blind control trial a year and a half ago that is the first one to be FDA approved and the only one to look at hemp-based CBD and right now we’re the only one to do it with any cannabis for people with CIPN. We have a goal of treating 100 patients and we’re 1/3rd of the way there. The trial is CBD and placebo for three months. After three months there is a one month wash out where we see what happens when you stop the product. After that we offer three months of CBD again. People don’t know if they have CBD or the placebo upfront, but later on, they will have access to CBD for three months free of charge. We’re not just looking at neuropathy, we’re also looking at factors like your energy level, your sleep, your anxiety, hot flashes, all kinds of symptoms, not just from CIPN. There’s been a lot of positive interest and we look forward to sharing the final results when the clinical trial concludes. To learn more about participation in our CIPN study, please email: 

What type of products did you use in your study?

 To do a randomized double blind controlled trial, the FDA scrutinizes the products. It has to be pharmaceutical grade. Most products out there that may be FDA approved are nutraceutical guidelines where the amount of CBD on the product has to be within 20% of what’s on the label. Pharmaceutical products have to be within 10% and also free of heavy metals, pesticides, and mold. Cannabis is a bioremediator product, it is a plant that you would use for centuries to clean fields because it has the amazing ability to suck all the junk out of the ground. So it’s very important that the source of hemp or marijuana is medical grade. You have to be sure that you see a certificate of analysis (COA) so that you don’t expose yourself as a patient, especially a cancer patient, to the junk that could be in these products. Mold, arsenic, mercury, or other stuff. So the FDA scrutinizes the product. We’re using medical grade products and have COA’s on everything that we use.

Through our study we learned that of the people who are using cannabis, 79% were using it during treatment which is pretty scary when you think about what’s in treatment like chemotherapy, radiation and you add to that a cannabis product that may be vaped or smoked or something like that. You want to make sure these products are safe. So it was clear we needed to learn more about the basis for which these products are used, that means doing more research to establish a better understanding of knowledge to base medical decisions on that would be required to get FDA approval and insurance companies to pay for this type of medical care.


 Well let me just encourage patients to participate in clinical studies. We’re very grateful to the people who’ve participated in our clinical study which has advanced the understanding of the role of cannabis and presented it to the largest organizations of cancer doctors. We’re very thankful to the participants of the clinical trial studies in the hospital because that’s how we’re going to get a better understanding of what cannabis does and doesn’t do and with that we can give people a better quality of life and increased odds of survival.

But just like in other aspects of your care, you have to be your own best advocate. If you don’t let your doctor know how they can be helpful to you, then you might not be heard, you may not get help and you’re the one who will miss the opportunity for better care. So be the one to ask.

Dr. Marissa Weiss is the author of four critically acclaimed books on breast cancer and breast health: 

, coauthored with her mother, Ellen Weiss (1998, 2010); 

Taking Care of Your “Girls:” A Breast Health Guide for Girls, Teens, and In-Betweens

, coauthored with her daughter, Isabel Friedman (2008); and 

7 Minutes!: How to Get the Most from Your Doctor Visit 

(2007). A renowned leader in the field of breast cancer, Dr. Weiss is frequently called on by the media as a subject matter expert and respected voice of breast cancer patients.

 is the Executive Director of Americans for Safe Access (ASA), a medical cannabis patient advocacy non-profit whose mission is to ensure safe and legal access to cannabis (marijuana) for therapeutic use and research. Debbie oversees all organizational and program operations in regards to education, training, policy, research, product safety and business compliance. Current projects include national campaigns such as ASA’s End Pain, Not Lives campaign and No Patient Left Behind campaign and programs such as ASA’s Patient Focused Certification (PFC) program and the Cannabis Care Certification (CCC) program. She serves as a writer and final editor on ASA publications including the 

Medical Cannabis Access for Pain Treatment

Dr. Marissa Weiss offers some tips and talking points to help patients start a conversation about the therapeutic use of cannabis for breast cancer.

The earliest scientific research on the effects of cannabinoids on cancer cells date back to the mid-1970s, with Louis Harris’ investigations of tetrahydrocannabinol's (THC) inhibition of cancer growth (1,2). Research on cannabis as a potential treatment specifically for breast cancer didn’t begin for another 20 years, until the 1990s. Since then, there have been several thousand preclinical studies, most of which have been conducted only within the last 10 years. Scientific research on breast cancer is thus still in its early stages. What have we learned about cannabis to treat breast cancer? Let’s take a look.

Breast cancer tumors are extremely heterogeneous in nature, as noted by Rahman and colleagues (3): “Breast cancer shows intra-tumor heterogeneity at molecular, genomic and phenotypic levels.” One aspect of this diversity is tumor cells’ different patterns of expression of both hormone receptors and cannabinoid receptors.

The most reliable way of stratifying different breast cancer types is that based on hormone receptor expression, that is, whether or not the tumors contain estrogen receptors (ER), progesterone receptors (PR), or human epidermal growth factor receptor 2 (HER-2). The presence of any of these hormone receptors provides a target or pathway by which to attack the cancer (see 

Breast cancer tumors that express hormone receptors (Luminal A, Luminal B, or HER-2+) may be treated using hormone therapy, which interferes with the body’s own production and effects of these hormones on promoting tumors. However, breast cancer tumors that do not express hormone receptors (triple negative breast cancer, or TNBC) do not respond to hormone therapy. Other treatment options for all breast cancer types include chemotherapy (oral or IV administration of drugs to stop cancer cell growth) or radiation therapy (4).

Cannabis Has Diverse Effects on Breast Cancer

Cannabis has been found to “selectively and differentially affect” different types of breast cancer cells (5). This is due to a combination of factors. First, the patterns in which cannabinoid receptors (CB1 and CB2) are expressed on tumors differ across cancer cell types (3,5). Next, CB2 receptors are more prevalent than CB1 receptors: CB1 is detected in 28% of breast cancer carcinomas, while CB2 is detected in 72% of carcinomas, where both CB1 and CB2 are found more often in HER-2 positive tumors (3). Finally, different cannabinoids that bind to the same type of receptor can cause different downstream effects on cancer cells. This phenomenon is known as 

Research on Cannabis Use for Breast Cancer

There is a large body of preclinical and clinical research that includes all three forms of cannabinoids: endocannabinoids (made by the body), phytocannabinoids (made by plants), and synthetic cannabinoids (man-made). The research examines how cannabinoids may be used to treat cancer in general, as well as to treat specific forms of cancer, such as astrocytoma, glioblastoma, head and neck, breast, Hodgkin lymphoma, leukemia, skin, and squamous cell cancer. The research reported herein is focused specifically on studies of cannabinoid treatments for breast cancer.

Cannabis has been found to provide relief to breast cancer patients in three different ways: (i) cannabis addresses the symptoms associated with either the cancer itself or the side effects from cancer medications; (ii) cannabis increases the efficacy of complementary cancer treatments; and (iii) cannabis attacks the cancer itself. At the same time, however, a few studies have, in fact, found that cancer may 

 tumor growth in breast cancer cells. Let’s take a closer look at what the studies have to say for each of these types of effects of cannabis on breast cancer.

Addresses Symptoms and Side Effects of Treatment

The list of side effects associated with cancer and cancer treatments is lengthy. Commonly reported side effects include, among others, pain, anxiety, depression, fatigue, insomnia, nausea or vomiting, and weight problems (7). There is a large body of research supporting the efficacy of cannabis for use in treating most of these symptoms and side effects of breast cancer.

Surveys of patients with breast cancer indicate that a significant portion of patients (42% in one study) have used cannabis to treat their symptoms. These patients tend to find cannabis provides relief for most symptoms or side effects, including insomnia; joint and muscle aches, discomfort, stiffness, or pain; anxiety, stress; and nausea or vomiting (8,9).

No clinical trials have yet been performed to assess cannabis’s efficacy for treating symptoms and side effects specifically of breast cancer. However, many clinical trials of generic “cannabis,” as well as of specific cannabinoids have been tested and shown to be efficacious for treating symptoms generally associated with cancer and cancer treatment, including nausea or vomiting, pain, appetite, fatigue, anxiety, and depression. Notably, three of the four cannabis pharmaceuticals that have been government-approved—Dronabinol (1986 in US), Nabilone (1981 in Canada, 1985 in US), and Sativex (2010 in UK)—were approved to treat cancer-related symptoms and side effects. [Note: The fourth cannabinoid pharmaceutical approved for medical use is Epidiolex, approved by the FDA in 2018 for the treatment of epilepsy.]

Increases Effectiveness of Traditional Treatments

In preclinical studies, researchers have shown that cannabinoids enhance the anti-cancer effects of various other chemotherapy treatments in breast cancer cells (10), as well as in other cancer cell types (11).

Scientists have discovered multiple pathways for preventing the growth and spread of breast cancer cells. Preclinical studies have well-established the potential for cannabis to address most of these pathways. Yet, while there are case reports, there have not yet been any clinical studies on cannabis for preventing the growth or spread specifically of breast cancer.

Preclinical studies on breast cancer cell lines have established the following findings.

Caffarel and colleagues provide a succinct description of 

, together with cannabis’s role in managing the process when it goes awry (12): "There are very few critical decisions that cells must take during their lifetime. Basically, these are whether to proliferate, differentiate, or die. A tight regulation of the cell cycle is crucial to control all these decisions, and its deregulation has devastating consequences, such as cancer. It has been proposed that cannabinoids, the active components of 

, play a role in the control of the aforementioned decisions. For example, they can modulate survival, proliferation, and differentiation depending on the cell type and its physiopathologic context."

 is the speed at which cancer cells replicate themselves. “If the cancer cells are dividing more rapidly, it means the cancer is faster growing or more aggressive” (13). There is a substantial body of preclinical research establishing that endo-, phyto-, and synthetic cannabinoids inhibit the proliferation of breast cancer tumors with cell types ER+ (11,14), HER-2+ (15,16), and TNBC (15,17).

 is a natural process used by the body to rid itself of unneeded or abnormal cells (19). As with cell proliferation, there is also a substantial body of preclinical research establishing that endo-, phyto-, and synthetic cannabinoids promote apoptosis in breast cancer tumors with cell types ER+ (12,21), HER-2+ (12), and TNBC (21-22).

—the formation of new blood vessels—through which tumors draw their resources (23). Several preclinical studies show that endo- and synthetic cannabinoids block angiogenesis in TNBC (24,25).

Blocks Invasion, Metastasis, and Migration

Cancer cells spread from one location in the body to another using a specific process, called 

 of individual cells that detach from the primary tumour, enter lymphatic vessels or the bloodstream and seed in distant organs.” There is a substantial body of preclinical research establishing that endo-, phyto-, and synthetic cannabinoids inhibit invasion, metastasis, and migration in breast cancer tumors with cell types ER+ (6,18), HER-2+ (3,6,14,16), and TNBC (3,6,14,16).

Despite a wealth of studies supporting the breast cancer-fighting effects of cannabis, there are two studies that have shown that cannabis may actually promote tumor growth in breast cancer cells. Noteworthy is the fact that in both of those cases, the researchers indicated that the breast cancer cells that were examined expressed “low to undetectable levels of cannabinoid receptors” (20,29). The lack of cannabinoid receptors could thus be used as a marker for cases in which cannabis should not be used for cancer therapy.

Breast Cancer Markers for Cannabinoid Treatment

So, what we have is that breast cancer is diverse and may be classified based on the types of receptors the breast cancer cells express. In particular, a large portion of breast cancer cells have cannabinoid receptors and should thus react to cannabis. Indeed, surveys of breast cancer patients indicate that a significant portion of patients uses cannabis to relive symptoms, and clinical studies establish the efficacy of cannabis to treat the symptoms of cancer in general as well the side effects of cancer treatments. While clinical evidence assessing the benefits of cannabis for treating breast cancer have not yet been conducted, there is a large body of preclinical research establishing a theoretical basis for using cannabis, not only to treat the symptoms of breast cancer, but also to attack the cancer itself. Yet, there is reason for caution, as a few studies have shown that cannabinoids may, in fact, promote the growth of breast cancer cells.

So, then, what we need is a good marker not only for determining when cannabinoids should be considered as a treatment for breast cancer, given cannabis’s anti-cancer potential, but also for determining when cannabinoids should 

 be considered for treatment, due to its pro-cancer potential.

Cannabinoid receptors (CBRs) are not expressed in non-tumor breast tissue (12,32).

Cancer cells that have higher CBR expression tend to be more aggressive (11,12,15,31,32), as well as more responsive to cannabis (29,31,32).

Cancer cells that have lower CBR expression tend to be either less responsive to cannabis (12) or even stimulated by cannabis (11,29,30).

Cannabinoids may suppress immune system functioning (31).

Taken together, researchers have concluded that when CBR expression is low, then the negative effects of cannabinoids on inhibiting other immune responses to cancer growth outweighs any tumor-suppressing effects cannabinoids might have (30,31). Clearly, then, when CBR expression on breast cancer tumors is low, cannabinoids should not be considered as an anti-cancer therapeutic.

If, on the other hand, CBR expression on breast cancer tumors is high, then the beneficial effects of cannabinoids on suppressing tumor activity outweigh their negative effects on suppressing immune system activity (30,31). So, then when CBR expression on breast cancer tumors is high, cannabinoids should be considered as an anti-cancer therapeutic.

(1) L. Harris, A. Munson, M. Friedman,. et al, "Retardation of tumor growth by D9-tetrahydrocannabinol," 

(2) A. Munson, L. Harris, M. Friedman, W. Dewey, and R. Carchman, "Antineoplastic Activity of Cannabinoid," 

 DOI: 10.1093/jnci/55.3.597. Retrieved from 

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Ruth Fisher, PhD, is a systems design researcher and analyst. She analyzes markets to determine how environments shape outcomes. She is co-founder of CannDynamics, Inc., and author of 

The Medical Cannabis Primer and Winning the Hardware-Software Game: Using Game Theory to Optimize the Pace of New Technology Adoption.

 Dr. Fisher has worked in the technology and healthcare sectors on behalf of technology companies, early-stage researchers, physicians, and technology start-ups.

Scientific research on breast cancer is still in its early stages, but here we take a look at what we have learned about cannabis to treat breast cancer thus far.

The question of whether cannabis can be a treatment for cancer has intrigued researchers for years. But as more and more patient and doctor anecdotes about using cannabis for cancer treatment begin to surface, there is a growing expectation that this ancient medicine may actually be able to do more.

One of those stories of cannabis treatment for cancer comes from cancer survivor Nicole DiMonda, who, along with her husband, Jaime Brambila faced life and death decisions and turned to cannabis for answers.

Breast cancer survivor Nicole DiMonda and her husband, Jaime Brambila, share their story of life and death decisions and how they turned to cannabis for help.

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