SGO Palliative Care Series: Medicinal Cannabis in Cancer Care | Diana English, MD; Albert Pisani, MD; Ashley Greenwood, MD; Eloise Theisen, NP, AGPCNP-BC; Lindsay Brubaker, MD; Sandy Trieu, MD

The SGO Palliative Care Committee is excited to present a series of recaps from our 2023 Annual Meeting education sessions. Our second blog features Medicinal Cannabis in Cancer Care presented by Drs. Diana English, MD, Al Pisani, MD, Ashley Greenwood, MD, Lindsay Brubaker, MD, Sandy Trieu, MD, and Eloise Theisen, NP, AGPCNP-BC.

As many as 24-40% of cancer patients in the U.S. use cannabis. The most common reported reasons for the use of medicinal cannabis in cancer care include limiting the impacts of cancer and its effects, such as refractory nausea and vomiting, improving appetite, promoting sleep and reducing opioid requirements.

Definitions:

Cannabis: the genus that includes 3 plant species: Cannabis sativa, Cannabis indica and Cannabis ruderalis. Source of fiber, food, oil and medicine.

Hemp: stalks, stems and sterilized seeds of Cannabis sativa. Very low concentration of tetrahydrocannabinol (THC) < 1%. Non-medicinal part of the plant.

Marijuana: leaves, flowers and viable seeds of Cannabis sativa. Higher concentration of psychoactive THC, 5-20%. Medicinal part of the plant.

Cannabinoids: naturally occurring compounds found in Cannabis plant and includes THC and cannabidiol (CBD).

The legal landscape for cannabis use in the United States has changed significantly since 1851 when it was first included in the U. S. Pharmacopoeia, a compendium which published detailed instructions on Cannabis preparations for medicinal use in 1916. There was not much regulation regarding cannabis until 1970, when Congress passed the Controlled Substances Act (CSA) and created the Drug Enforcement Agency (DEA). The CSA created a Schedule I – V system of categorizing drugs with abuse potential which the DEA still enforces today. Cannabis was designated a Schedule I drug, reserved for “drugs with no currently accepted medical use and a high potential for abuse.” Cannabis remains illegal at the federal level, but the last five decades have seen a watershed change in state law relating to cannabis. The first state to legalize cannabis for medicinal use was New Mexico, in 1978, but only for patients participating in federally-approved research trials. At present, only two states in the U.S. do not allow the legal use of cannabis for any purpose: Idaho and Nebraska. Laws regarding medicinal cannabis use vary greatly from state to state. Penalties imposed for illegal use of cannabis also vary from state to state, ranging from no penalty or minimal jail time and fines less than $500 (California) to 1-5 years of incarceration with fines up to $50,000 (Idaho). Providers and patients would be well advised to check the status of laws in their local jurisdiction, and may find additional information at the following websites: https://www.ncsl.org/health/state-medical-cannabis-laws and https://norml.org/laws/.

All living organisms have an endocannabinoid system (ECS) which helps to maintain homeostasis. The ECS modulates appetite, emotion, memory, and pain and is composed of at least 2 receptors (CB1 and CB2). These receptors are found throughout the brain and body and are the most abundant of any system. There are three categories of cannabinoids that interact with the ECS: endogenous cannabinoids, phytocannabinoids, and pharmaceutical cannabinoids. Phytocannabinoids are found in numerous plants, not just cannabis. The most common are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Pharmaceutical cannabinoids are either plant-derived or synthetic, for example, dronabinol. Cannabis preparations are available in several routes: oral, inhaled, topical, and rectal (Table 1). The general recommendation for dosing is to start low and go slowly. The recommended starting dose of THC or CBD is 5-10mg. Greater than 25mg of CBD has been shown to help with sleep and anxiety. CBD is biphasic and low doses may be stimulating and larger doses may be sedating.

Rick Simpson’s Oil (RSO) is a highly concentrated form of THC and/or CBD. It often comes in a syringe for oral use and it is difficult to accurately dose due to high viscosity. Patients often unintentionally overconsume and RSO is not appropriate for an inexperienced user who may sensitive to THC. The most common adverse reactions to cannabis products are dizziness, sedation and increased anxiety. Too much cannabis can cause hyperemesis, catatonia, acute coronary syndrome and acute pancreatitis, but not death. There is no lethal overdose of cannabis.

There are several studies of medicinal cannabis in cancer care, however randomized controlled trials are limited. According to the National Academy of Sciences, Engineering and Medicine Report on Health Effects of Cannabis and Cannabinoids, there is conclusive evidence that cannabis is effective for chronic pain in adults. Additionally, clinical studies have shown that cannabinoids are opioid sparing and offer benefits for management of cancer-related pain. Randomized controlled trials have additionally showed statistically significant reduction in peripheral neuropathy for patients using cannabis compared to placebo.

There is also substantial evidence that cannabis is effective for chemotherapy-induced nausea and vomiting. The Food and Drug Administration has approved the cannabinoids, dronabinol or nabilone to treat nausea and vomiting that is resistant to standard antiemetic therapies. Cannabinoids have also been found to have synergistic potential in nausea and vomiting when combined with other antiemetics.

The National Academy of Sciences, Engineering and Medicine report concluded that there was moderate evidence in support of the use of cannabis for secondary sleep disturbances. The evidence was limited, insufficient or absent for the use of cannabis for appetite, anxiety/post-traumatic stress disorder or cancer.

In summary, cannabis remains a schedule I drug, while pharmaceutical grade cannabinoids are schedule III. Cannabis remains illegal at the federal level, but nearly half of states allow medicinal cannabis. There are natural cannabinoids (THC, CBD) and pharmaceutical cannabinoids (dronabinol). Cannabis preparations are available in several routes: oral, inhaled, topical, and rectal. The general recommendation for dosing is to start low and go slowly. There is good evidence to support use of cannabis and cannabinoids in cancer care, particularly when considering nausea/vomiting and chronic and neuropathic pain.

Clinician Resources

1. National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Board on Population Health and Public Health Practice; Committee on the Health Effects of Marijuana: An Evidence Review and Research Agenda. The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research. Washington (DC): National Academies Press (US); 2017 Jan 12. 4, Therapeutic Effects of Cannabis and Cannabinoids. Available from: https://www.ncbi.nlm.nih.gov/books/NBK425767/
2. PDQ Integrative, Alternative, and Complementary Therapies Editorial Board. Cannabis and Cannabinoids (PDQ®): Health Professional Version. 2022 Jun 7. In: PDQ Cancer Information Summaries [Internet]. Bethesda (MD): National Cancer Institute (US); 2002-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK65755/
3. National Academy for Science, Engineering and Medicine: https://www.nap.edu/catalog/24625/the-health-effects-of-cannabis-and-cannabinoids-the-current-state

Authors

Diana English, MD, is a gynecologic oncologist at the University of South Florida in Tampa, FL.

Eloise Theisen, NP, AGPCNP-BC, is a nurse practitioner at Stanford Health Care in San Jose, CA.

Ashley Greenwood, MD, is a gynecologic oncology fellow at the University of Colorado in Aurora, CO.

Sandy Trieu, MD, is a palliative medicine doctor at Stanford Health Care in San Jose, CA.

Albert Pisani, MD, is a gynecologic oncologist at the Palo Alto Medical Foundation in Mountain View, CA.

Lindsay Brubaker, MD, gynecologic oncologist at the University of Colorado in Aurora, CO.

Diana English, MD

Eloise Theisen, MD

Ashley Greenwood, MD

Sandy Trieu, MD

Albert Pisani, MD

Lindsay Brubaker, MD