Medical Cannabis in Palliative Care: Meaningful Additions to the Research Evidence

Palliative care team members need to understand what is known and unknown about cannabis's health effects for individuals with high physical, emotional, or existential symptom burden because cannabis use is increasing even though health care practitioners may feel unprepared to counsel their patients. ¹ As of June 2019, 33 states and the District of Columbia have legalized medical cannabis use, and 11 states and the District of Columbia have legalized recreational cannabis use among adults. Use is permitted in other countries around the world, including Canada, the Netherlands, and Germany.

During telehealth palliative care clinics for adults with serious illnesses in Southern Colorado, we routinely ask “Do you use marijuana?” We do not ask, “Do you smoke marijuana?” or “Do you use medical marijuana?” or “Do you use edibles?” Such questions would be too closed-ended and limit a discussion of the multiple ways our patients may use cannabis. Indeed, one of our recent studies from a Colorado statewide mixed methods study of older adults found that “mixed use” is very common. ² Older adults who had used cannabis in the past year described using it for multiple reasons, in multiple forms (i.e., smoking or vaping, topical preparations, and edible forms), and obtaining it from multiple sources—both medical and recreational dispensaries.

This October 2019 issue of the Journal of Palliative Medicine provides a robust compilation of 11 articles focusing on medical cannabis use in palliative care. Together, these studies provide meaningful additions to the research evidence. The settings range from children's hospice in the United Kingdom to a rural academic outpatient palliative care clinic in Western New Hampshire (Wilson et al.). Several studies address patients living with cancer, including those seen at comprehensive cancer centers (Reblin et al.), outpatient palliative medicine programs (Carr et al.), or individuals with and without cancer who obtained cannabis through a large medical cannabis dispensary in New York (Kim et al.).

The study Donovan and colleagues answers the question, “How common is cannabis use among cancer patients seeking specialized palliative or supportive care at a comprehensive cancer center?” The answer is nearly one-fifth, based on testing positive for tetrahydrocannabinol (THC) on urine drug testing that is a routine practice at all initial visits to the Supportive Care Management Clinic at this Florida-based center. In this population, cannabis use was associated with moderate-to-severe symptoms, such as lack of appetite, shortness of breath, tiredness, difficulty sleeping, anxiety, and depression, despite the lack of high-quality evidence for effectiveness in palliative care.

To understand the effectiveness of medical cannabis for common palliative care symptoms, Casarett et al. used a national Canadian patient portal to determine patient self-efficacy ratings of efficacy from use of THC and cannabidiol (CBD) for common palliative care symptoms: neuropathic pain, anorexia, anxiety symptoms, depressive symptoms, insomnia, and post-traumatic flashbacks. Individuals using increased THC:CBD ratio had improved responses for neuropathic pain, insomnia, and depressive symptoms. Importantly, this study addressed common symptoms, but was not specifically among persons with known serious illness diagnoses. Efficacy studies of medical cannabis, plant-derived or synthetic cannabis-based medicine in palliative care settings remain rare. A recent Cochran review was able to include 16 randomized clinical trials of cannabis-based medicines for chronic neuropathic pain in adults. ³

Especially in the lay press, many reports tend to describe the positive benefits of medical cannabis use with less attention to side effects or risks. There are relatively fewer rigorous studies that assess for potential side effects. The case study and narrative review by Dr. Howard provides a contemporary assessment of the literature on cannabis hyperemesis syndrome and present unique considerations for clinical assessment and treatment for patients at end of life. Importantly, clinicians must be aware of atypical presentations of cannabis hyperemesis syndrome in the palliative care setting. This article highlighted for me the added complexity of evaluating the cause of nausea, vomiting, and abdominal pain among patients with serious illnesses in any clinical setting, rather than the prototypical features of someone presenting to the emergency department with chronic cannabis use, severe cyclical nausea and emesis, and frequent hot bathing.

The National Consensus Project Clinical Practice Guidelines for Quality Palliative Care highlight the ethical and legal aspects of palliative care, and specifically mentioned medical cannabis as an evolving treatment with legal ramifications. ⁴ The guidelines outline that the provision of palliative care should occur in accordance with existing regulations and laws, as well as current accepted standards of care and professional practice. The British survey of children's hospices by Tatterton and Walker explores the question, “How do you manage cannabis oil in your hospice?” Despite cannabis being a schedule I drug in the United Kingdom, 87.5% of the 40 hospices knew of children who use cannabis oil therapeutically and highlighted how the lack of available facility or health care team member guidance made decision making more challenging. Another study surveyed U.S. hospice staff members from 310 hospices to assess their comfort level with medical cannabis use in hospice (Costantino et al). Taken together, these studies describe the wide variations in current approaches among hospice organizations, and likely reflect the experiences of palliative care organizations as well as nursing and residential care facilities. Undoubtedly, these are practical and contemporary challenges to providing person-centered care in an evolving legal landscape and the lack of evidence-based policies and guidelines related to the use of medical cannabis as part of palliative care.

Last, but not least, and at the core of palliative care, are the voice and preferences of the patient. Tanco et al. conducted a survey to understand the attitudes and beliefs of cancer patients in a legalized (Arizona) versus nonlegalized state (Texas) regarding medical and recreational legalization and medical usefulness of cannabis. Among these patients who were seen by palliative care teams in outpatient comprehensive cancer centers, large majorities of individuals from both states supported legalization of cannabis for medical use and believe in its medical usefulness, including preferring cannabis over current standard treatments for anxiety. As palliative care team members seeking to provide holistic and person-centered care, we can only expect more requests from our patients and families to integrate cannabis use of all types and sources to help improve symptoms and quality of life.