CBD to THC: M.D. Unpacks 11 Qs About Cannabis for Cancer Symptom Relief

April 25, 2024
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We talk with a palliative care clinician about the potential benefits & risks of using medical cannabis (medical marijuana) to ease cancer pain and other symptoms — and why getting clinical guidance is key. 


Note: The Cancer Support Community does not provide medical advice. This blog is not intended as an endorsement for the use of medical cannabis and is not intended to replace the medical advice of your healthcare team. Always consult with your oncology provider before using cannabis and any alternative medicine interventions in your cancer care regimen. Some but not all states have legalized medical cannabis. Please check your state’s laws.


Can cannabis help relieve nausea from chemotherapy? 

What about cancer-related pain? 

Can cannabis improve sleep when struggling with insomnia after a cancer diagnosis?

Could cannabis use hinder cancer treatment?

If you or someone you love is going through cancer, you may have asked these or other questions about the safety and effectiveness of using cannabis to cope with cancer symptoms and treatment side effects. 

To get answers, we talked with palliative care clinician and researcher Brooke Worster, M.D., Chief Medical Officer at EO Care, a clinician-based cannabis consultation service for patients with chronic medical conditions. 

This Q&A with Dr. Worster is designed to provide a general overview of cannabis and cancer. Making an informed decision about using cannabis for cancer symptom relief should always include a discussion with your oncology team.

What are the potential benefits of cannabis for cancer patients? 

Dr. Worster: Potential benefits include improved control of cancer pain and neuropathy related to chemotherapy; relief of chemotherapy-induced nausea; appetite stimulation; and reduced anxiety.

There is also evidence that cannabis may reduce reliance on opioids in cancer and survivorship. There is little evidence that cannabis helps with primary insomnia in patients with cancer, but it can improve sleep disturbances, such as trouble falling asleep or staying asleep, when related to pain or anxiety. 


CBD and THC are two common cannabinoids used in cannabis products. What are the main differences between CBD and THC, and how do they work to help provide symptom relief? 

Dr. Worster: Cannabinoids are the group of chemical compounds found in the cannabis plant that have physical and mental effects when they interact with the cannabinoid receptors in your cells. The two most common are THC and CBD.

THC is the primary intoxicating cannabinoid. It is the component of cannabis that can make people feel “high.” THC receptors target motor activity, thinking, motor coordination, appetite, short-term memory, pain perception, and immune cells. 

THC is federally illegal, and legal on a state-by-state basis for recreational and/or medical use. To get well-regulated, labeled, and chemically tested THC products, state-regulated dispensaries are the only current way people can purchase high-THC products.

CBD is the primary non-intoxicating cannabinoid. CBD receptors target the reproductive system, immune system, cardiovascular system, respiratory tract, gut, kidneys, and more. CBD is federally legal, meaning that it can be purchased online and in person from trusted retailers.

There is some evidence that high-dose CBD may be most helpful for anxiety and sleep, but more research is needed. Despite this, studies have shown that patients more frequently report using high-THC cannabis for sleep. This is likely because many more high-THC products are available in state-regulated dispensaries.


Has there been any significant research to support the benefits of using cannabis to relieve cancer symptoms and treatment side effects?

Dr. Worster: Yes, a number of studies support the use of guided cannabis care to help address cancer symptoms and the side effects of treatment. The EO Care website shares a collection of clinical and scientific research that informs our methodology. 


What are some common barriers to getting reliable information about using medical cannabis?

Dr. Worster: Patients don’t know where to access reliable, medically sound information about cannabis. They often turn to dispensaries or friends and family for guidance. Despite their best intentions, dispensary staff are not medical professionals and simply lack the medical knowledge to responsibly partner with a cancer patient or survivor.

A Google search will generally lead patients to webpages geared toward recreational users or "pot docs." Some M.D.s or DOs will charge patients a fee to give them access to a medical card. They rarely give solid guidance and typically lack the evidence and tools to make personalized and detailed recommendations — including the most useful kind of product needed by the patient and the appropriate dosage. In addition, they usually lack the necessary time needed to understand patients’ individual needs.

Providing ongoing, timely support and partnering closely and responsibly with the patient to arrive at and maintain an optimal regimen takes time and doesn’t work for most cannabis M.D.s’ practice models. Cannabis doctors are also prohibitively expensive. Most charge $50-$350 per appointment, putting ongoing, collaborative care out of reach for most patients.


How can cancer patients overcome the stigma associated with using medical cannabis?

Dr. Worster: While attitudes are steadily improving, it’s possible that patients will encounter people who still carry a stigma against medical cannabis. Often much of this stigma is also tightly bound to fear of arrest, prosecution, or jail time, which has been sadly overused in prior decades for cannabis possession. In these cases, I recommend that patients have an open dialogue about their concerns with the people who have negative stigma or are not accepting of their use of cannabis as a palliative treatment.

Often, people are just unaware of the benefits or even how to legally access and use cannabis. Citing research is a good way to change minds. The truth is that cannabis use is not without risk. Rather than ignore the risks, identify and address them. With the appropriate guidance, risks are minimized and cannabis can provide real symptom relief.   


Note: Cannabis (marijuana) is not approved by the Food and Drug Administration (FDA) to treat cancer or its side effects. At this time, there are two drugs approved by the FDA that contain man-made forms of cannabinoids (compounds found in the marijuana plant). These drugs are intended for cancer patients who experience nausea and vomiting due to chemotherapy. 


Cannabis can be used in different forms. Smoked marijuana releases toxins and carcinogens that can harm the lungs and cardiovascular system
What forms of cannabis are considered safer to use medically?

Dr. Worster: There is increased evidence that smoking/inhaling cannabis causes both pulmonary and cardiac concerns. I avoid recommending that people smoke cannabis. Other forms such as capsules, gummies, tinctures, and inhalers are much safer. 


What are the potential risks of using cannabis products for cancer symptom relief?

Dr. Worster: Cannabis can be complicated. Most people are unaware of the products, doses, and times of use that can best address their symptoms, safely align with other medications in use, and fit their daily schedule.

Misuse can also create serious problems. Cannabis hyperemesis (frequent vomiting) has been shown to occur in over 33% of people who use cannabis over 20 times in a month.

Over a period of 12 months, 30% of regular cannabis users are at risk of developing a cannabis use disorder, meaning that their cannabis use has a persistent negative impact on their health, work, and/or social life. Patients need expert guidance in order to responsibly and efficiently identify a care regimen. It often takes weeks or even months to determine an effective treatment dose and form to improve uncontrolled symptoms. Such delays are unacceptable, especially when suffering is acute. 


What are some common cancer symptoms and treatment side effects that cannabis may help relieve? 

Dr. Worster: There is good evidence that cannabis can help with pain and, in some cases, can help reduce or prevent neuropathic pain. It may also provide real relief from chemotherapy-induced nausea and vomiting and improve appetite. CBD can help with anxiety. Relief from any of these symptoms may also lead to improved sleep quality.    


Can cannabis interact with cancer treatments, and in what ways?

Dr. Worster: There is some concern that cannabis can have an impact on reducing your immune response, which is helpful for alleviating discomfort associated with things like osteoarthritis and low back pain, but it may affect how immunotherapy (or immune checkpoint inhibitors ICI) works in your body. While this information is based on limited case-report type studies, it is important to have a conversation with your oncologist about cannabis if you are on any form of immunotherapy. 


Are there certain types that are better to use than others when you are in treatment?

Dr. Worster: This is a very personalized question, like what type of pain medication and dosing do you need or what antidepressant will work best in your body. This exemplifies why good guidance for cannabis is needed.


Are there situations when someone should not consider using cannabis to relieve cancer symptoms and side effects? 

Dr. Worster: Patients should consult with their clinician before beginning cannabis use. 

For patients who seek more information after consulting with their clinician, EO Care can provide additional guidance. EO Care works to decrease side effects or concerns about cannabis use, including when it may be high risk to an individual. To do this, we ask patients about their medical history, cancer treatments, medications they are taking, and prior use of cannabis. This helps EO Care develop a safe plan, and sometimes this plan is to say that cannabis may not be the right therapeutic for a patient.  

Learn About EO Care’s Services in Cancer Care


About Brooke Worster, M.D.

A pioneering palliative care clinician and researcher, Dr. Worster is currently Director, Supportive Oncology, at Jefferson Health in Philadelphia. She is a graduate of Temple University School of Medicine and completed her fellowships in palliative care and pain management at MGH Brigham and Dana Farber Cancer Center in Boston.