The American Society of Clinical Oncology has published new guidelines for the use of hemp cannabinoids by adults with cancer. They are based on current scientific knowledge about the feasibility of including cannabis and hemp extracts in cancer therapy. Let's take a look at some of the issues addressed in the ASCO guidelines.
Medical cannabis and hemp extracts in oncology - guidelines
On March 13, 2024, ASCO (American Society of Clinical Oncology) published guidelines for the use of cannabis and isolated cannabinoids by adults with cancer.
Guidelines were developed by scientists and medical oncologists based on data collected in a systematic, multi-step review of the scientific literature. The literature analysis considered both synthetic cannabinoids, extracts containing single hemp cannabinoids or combinations of cannabinoids, and full spectrum hemp products, including medical dried hemp.
ASCO guidelines discuss the scientific evidence regarding the effectiveness of cannabis as:
- anti-cancer therapy
- methods of managing the symptoms of cancer
- Side effects of cancer treatment.
According to the authors of the guidelines, with the current state of scientific knowledge, the use of cannabis and cannabinoids in oncology treatment should not go beyond treating vomiting and nausea after chemotherapy according to already accepted regimens, as well as some other ailments associated with cancer and its conventional treatment.
According to the guideline's authors, there is currently insufficient scientific evidence that cannabis cures cancer, and it should not be considered as an independent form of therapy, unless it involves patient(s) participation in a clinical trial. The researchers stress the need for further research on cannabis and/or cannabinoids.
ASCO guidelines - cannabis in oncology, Q&A
Due to the high level of interest in the guidelines, ASCO also published a Q&A section, which includes answers to a number of questions to help doctors educate patients, and to help sufferers themselves stay safe when using cannabis on their own.
Question 1: Shouldn't doctors talk to adult oncology patients about medical cannabis?
According to the authors of the guidelines, the opposite is true - the question about the use of cannabis products should be asked in every medical history. Data suggest that 20-40% of people with cancer in the US use cannabis.
Therefore, being up-to-date on what doses of cannabinoids patients/clients starting conventional cancer therapy are taking is very important. The full guidelines include suggestions for taking a history of cannabis and/or cannabinoid use.
Question 2: Is there any risk in the use of cannabis with THC by cancer patients/caregivers?
The guidelines read that side effects of tetrahydrocannabinol (THC)-based products include dizziness, mild confusion, dry mouth and fatigue. More serious side effects include drops in blood pressure when changing body position (Orthostatic Hypotension), severe confusion and high levels of anxiety.
The authors note that these side effects can be dangerous for the elderly, those weakened by illness, and those who have not developed a tolerance to THC.
Question 3: Does the mode of administration affect the effects of cannabis with THC?
The authors answer in the affirmative. The effects of hemp products with THC burned or vaporized occur within seconds/minutes and last for 2-3 hours. This also applies to the after-effect. In contrast, when administered orally, the waiting time for the effects to appear extends to 30 minutes-2 hours, and the effect can last up to 5-8 hours.
These differences can make a significant difference in the speed and degree of relief of disease symptoms, as well as in the well-being and safety of users. Adults with cancer who are using oral cannabis products for the first time should be aware that the time to take effect may be longer and refrain from taking subsequent doses too quickly.
Question 4: Do cannabis and cannabinoids interact with standard drugs and therapies used to treat cancer?
ASCO's response reads that yes, drug-cannabis interactions can occur in cancer therapy.
Preliminary observational data suggest that clinical outcomes may worsen in people who receive immunotherapy and use large amounts of cannabis at the same time (immunotherapy is a therapy that uses the body's immune system to stimulate, regulate or enhance the body's immune responses to fight cancer or other diseases).
Large human studies suggest that hemp cannabinoids modulate the immune system, and therefore may worsen the results of immunotherapy, which is supposed to achieve a similar goal by acting in a different way.
In addition, reversible liver enzyme elevations can occur with CBD-containing products if used in daily doses of 300 mg or more. Therefore, doctors should specifically ask adults with cancer about the use of CBD and inform them of this potential risk, especially when cancer therapy is associated with hepatotoxicity (the possibility of liver dysfunction or liver damage).
Question 5: Should cannabis be used to treat cancer?
According to the guidelines - not yet, there is currently insufficient scientific data to support its effectiveness as a separate form of human cancer therapy. Therefore, cannabis should only be used in oncology at this time as a means of alleviating some of the symptoms associated with standard cancer treatment.
The ASCO guideline authors emphasize that their position relates to the current state of scientific knowledge and may change in the face of new evidence. The primary recommendation for physicians is to be open to talking about patients' self-administration of cannabinoids, to be non-judgmental and honest in communicating potential risks, to keep track of patients' doses and types of cannabis products taken. All of this is expected to add up to greater safety in cancer therapy.
