In the current study, dubbed the Coala-T-Cannabis study, the investigators approached U.S. members of the Breastcancer.org and Healthline.com communities who self-reported that they had been diagnosed with breast cancer within the past 5 years; 612 surveys were completed.
Half of all respondents said they had looked for information on medical cannabis, but most were unsatisfied with the information that they had received. Only 6% were extremely satisfied; 25% were very satisfied with the information.
Most patients (39%) did not discuss cannabis use with their physicians. Of those who did, 28% reported feeling uncomfortable discussing the topic. Only 4% of survey respondents indicated that physicians were the most helpful source of cannabis information.
Regarding which source of information was most helpful, 22% said websites, 18% said family members or friends, 12% said staffers and pharmacists in dispensaries, and 7% said other patients with breast cancer.
Forty-two percent of the survey respondents said they used cannabis for medical purposes and for relief of symptoms, which included pain (78%), insomnia (70%), anxiety (57%), stress (51%), and nausea/vomiting (46%).
In addition, 49% believed that medical cannabis could be used to treat the cancer itself.
A fair number were also using cannabis for recreational purposes. Of those who used cannabis, only 23% reported that they used it for medical purposes only.
Participants used cannabis in a variety of forms. The most popular form of consumption was as edibles (70%), followed by liquids/tinctures (65%), smoking (51%), topicals (46%), and vape pens (45%). Participants reported using an average of 3.7 different products.
Safety concerns?
The authors caution about the use of cannabis while receiving anticancer therapies because such use “raises important efficacy and safety concerns.”
“Many chemotherapy agents as well as cannabinoids are metabolized in the liver’s p450 cytochrome system,” Dr. Weiss and colleagues note, and the mechanism by which cannabinoids interact with particular CYP450 isoenzymes “has the potential to alter the metabolism of other medications and lead to adverse side effects.”
They also question the safety of some of the cannabis products that are being used. Participants reported receiving cannabis from a variety of sources, which included state-regulated dispensaries, “dealers,” and family/friends.
Three-quarters of respondents believed that cannabis was better than “chemicals” and that the benefits outweighed the risks. But many of the products used are unregulated, the authors point out.
“Providers should communicate clearly about the health and safety concerns associated with certain cannabis products and methods of delivery,” they conclude. “Without these measures, patients may make these decisions without qualified medical guidance, obtain poor-quality cannabis products, and consume them through potentially hazardous delivery methods during various types of cancer therapies.”
The study was supported by research grants from Ananda Health/Ecofibre and the Dr. Philip Reeves Legacy Fund. Several coauthors reported relationships with industry, as noted in the article. Dr. Abrams owns stock in Cannformatics and Lumen; he has received honorarium from Clever Leaves and Maui Grown Therapies and speaker honorarium from GW Pharmaceuticals.
A version of this article first appeared on Medscape.com.