Cancer, Cannabis, and Choices: A Conversation of Hope and Caution

Beth, a 48-year-old woman, has recently started chemotherapy for Invasive Ductal Carcinoma (IDC) breast cancer. She is experiencing pain, poor appetite, and nausea, and is concerned about developing nerve damage as a result of chemotherapy. Beth has questions about using cannabis to help cure her cancer and has spent many hours reading about cancer patients who successfully treated their cancer with cannabis. Beth contacted a nurse, who is a certified cannabis consultant, to learn more about using cannabis during her cancer therapy.

Introduction to Cannabis and Cancer

Beth is not alone in wondering how cannabis might help with her cancer treatment. Many cancer patients are using cannabis to manage symptoms like nausea, pain, trouble sleeping, anxiety, and stress. In fact, between 20% and 40% of people going through cancer treatment use cannabis for these reasons (National Cancer Institute, 2024). Some patients also find that cannabis helps reduce nerve damage caused by chemotherapy, which is a common side effect for many cancer patients (Waissengrin, Barliz, et al., 2021). It is not an uncommon belief that because cannabis is “natural” it is safe and effective, but “natural” does not always mean it is safe. For example, taking high doses of Cannabidiol (CBD), a compound found in cannabis, can affect how your liver processes other medications. This can cause some drugs, including chemotherapy, to build up in your body to dangerous levels, leading to harmful side effects. This does depend on the dose, with lower doses showing no such effect (Zhu, Peltekian, 2019).

While some people believe cannabis might help fight tumors, the evidence isn't clear at this time. Most research showing potential anti-tumor effects has been done using animals or cells in a dish, not in actual humans (Abrams, 2022). The American Society of Clinical Oncology (ASCO) states the use of cannabis by adults with cancer has gotten ahead of the science supporting its clinical use (National Cancer Institute, 2024).

The Endocannabinoid System

The endocannabinoid system (ECS) is an important communication system within our body that helps manage various functions, such as learning, emotions, sleep, body temperature, pain, and how we respond to inflammation and infections. This system works through special molecules called endocannabinoids, which act like messengers. These messengers attach to specific receptors on our cells, influencing many bodily functions The main endocannabinoid receptors are CB1, found mostly in the brain and CB2 found in the rest of the body, including the immune system. Cannabis can kill cancer cells, while not harming healthy cells as well as preventing the spread of cancer.  Some studies suggest that our body's own endocannabinoids might have similar effects, but there isn't much research on this just yet (Russo, 2020; Costa, et al., 2016; Velasco, et al., 2016; Quang, et al., 2024; Hinz, Ramer, 2022). Cancer cells also have these CB receptors which is how cannabis exerts its anti-tumor effect. However, the presence of these receptors on cancer cells can also cause an increase in cancer progression. Whether or not cannabis can kill cancer depends on the specific cancer type, receptor expression levels, and other factors in the tumor microenvironment (Russo, 2020; Sarsembaayeva, et al., 2023).

How Cannabis Works

Cannabis contains compounds called phytocannabinoids, which have a similar molecular structure to our endocannabinoids and interact with the ECS receptors in a similar way. The main phytocannabinoids in cannabis are Tetrahydrocannabinol (THC) (which can make you feel "high"), Cannabidiol (CBD), and Cannabigerol (CBG). There are also over 100 other cannabinoids and terpenes in cannabis, and each of these contributes to how the plant affects us (Russo, 2020; Grinspoon, 2021). Not all cancer cells express endocannabinoid receptors, which means cannabis may not have any effect on them (Preet, et al., 2012; Russo, 2020; Moreno, et al., 2020; Elbaz, et al., 2017;  Dobovisek, et al., 2024 ).

Beth’s cancer, Invasive ductal carcinoma (IDC), is the most common type of breast cancer and can express CB1 and CB2 receptors, but the expression varies among different cases. Some early-stage studies suggest that phytocannabinoids might have the ability to fight tumors through these receptors in some breast cancers (Elbaz, et al., 2017;  Dobovisek, et al., 2024;  Moreno, et al., 2020). However, animal studies have shown that THC can enhance the growth of certain breast cancers by weakening the immune system (Shalata, et al., 2024; Realm of Caring; McKallip, et al., 2005). Other studies have suggested that cannabis can make immunotherapy treatments less effective (Taha, et al., 2019). There are some studies that show  CBD appears to be less immunosuppressive than THC (TGA, Eisenstein, 2015, Nagarkatti, et al., 2009 ). Therefore, it is important to weigh the risks and benefits of cannabis use during cancer treatment.

THC, CBG, and CBD can help with pain, sleep, and nausea. CBD can be helpful with inflammation and may limit nerve damage as well as act to counter nausea (Bathula, Maciver, 2023; Rock, et al., 2021; Mazanet, 2017; Mezzanotte, et al., 2023). THC can help relieve pain by reducing pain impulses in the brain and CBG can help with anxiety and insomnia by interacting with the GABA receptors in the brain (Goldstrich, 2023).

Dosage and Administration

Cannabis, in low doses, may help improve the quality of life for patients dealing with the side effects of cancer treatment. It is recommended to take the smallest dose necessary to obtain the desired results. For those patients using cannabis with the hope of killing cancer cells, high doses are often used, such as a gram a day of highly concentrated extract (60-80%) (Pharmture). However, high doses can depress the immune system and cause gastrointestinal disturbances, not to mention causing psychoactivity if the cannabis is THC dominant (Shalata, et al., 2024). In mice, about 8 mg of THC per kilogram of body weight (which translates to about 550 mg for a 70 kg person) has been found to weaken the immune system, especially the part that involves cells working together to fight off infections (Klein, et al., 2000). CBD is generally thought to have a less intense effect on the immune system compared to THC. However, it can still weaken the immune response and cause certain immune cells to die off (Maggirwar, Khalsa, 2021). This could be a concern, such as when being treated with immune checkpoint inhibitors. In this case, it may be a good idea to use the lowest dose possible to treat symptoms such as insomnia, nausea, and pain. Being unable to sleep well can also have a negative impact on the immune system. Sleep is imperative for a healthy immune system (NIH-funded study shows sound sleep supports immune function, 2022.

Legal and Safety Considerations

When it comes to using cannabis, ingesting it might be a better option than inhalation. This is because inhaling cannabis smoke can harm the immune cells in your lungs and make you more susceptible to viruses. Smoking cannabis regularly can weaken your lungs' ability to fight off infections (Maggirwar, Khalsa, 2021). Many patients use concentrates such as Rick Simpson Oil (RSO), which is a full-spectrum, highly concentrated form of cannabis that is ingested. Preclinical studies suggest that full-spectrum cannabis extracts may have greater anti-tumor effects compared to isolated cannabinoids due to the "entourage effect," where cannabinoids and terpenes work synergistically (Abrams, 2022; Worster, 2022).

it is important to understand the legal issues surrounding cannabis, as cannabis laws vary by state and it’s prohibited on flights and in many countries.  

According to the National Institute on Drug Abuse (NIDA), there has not been a documented case of anyone dying from a cannabis overdose. While cannabis isn’t lethal like opiates, it can be addictive, and withdrawal symptoms can be very challenging for some patients (The Recovery Village). In fact, 47% of cannabis users experience withdrawal when they stop or significantly reduce their cannabis consumption (Bahji, et al., 2020).

In conclusion, cannabis can be a valuable tool for managing the symptoms of cannabis and the side effects of cancer treatment, such as nausea, pain, poor appetite, and insomnia, but it is crucial to approach its use with caution and consult your health care team. While there is potential for anti-tumor effects, these have not been proven through gold-standard studies done on humans and in fact cannabis may even interfere with cancer treatment. It is therefore important to consider the legal implications and potential adverse effects when using cannabis in the treatment of cancer.

References

1.      Goldstrich, JD, MD, FACC, (2023) The cannabis Cancer Connection, Flower Valley Press

Assessed and Endorsed by the MedReport Medical Review Board