A Survey of Breast Cancer Patients’ Use of Cannabis During Radiation Therapy

Purpose/objective(s): Cannabis use is rapidly expanding and cancer is a qualifying condition in all 33 states allowing medical cannabis. However, the patterns of cannabis use among breast cancer patients receiving radiation therapy is unknown. The goal of this study was to better understand how and why cannabis is used among breast cancer patients undergoing adjuvant and palliative radiation therapy.

Materials/methods: Between 12/16/2019 and 1/19/2020, U.S.-based members of the Breastcancer.org Community (a nonprofit organization providing medical information and peer support) and Healthline, ≥ age 18 and diagnosed with breast cancer within 5 years, were invited to participate in a cannabis survey. After informed consent, anonymous data were collected and analyzed in aggregate. The study was led by Socanna (advancing the science of cannabis), conducted by Outcomes Insights, and supported by a grant from Ananda Health/Ecofibre.

Results: A total of 725 were screened and met eligibility criteria, of whom 612 subjects completed the survey. Overall, 42% (257/612) of participants had used medical cannabis products to relieve breast cancer symptoms or treatment side effects. Of the 120 respondents who received adjuvant radiation, 49% (59/120) used cannabis during breast radiotherapy; and 47% (14/30) used cannabis during palliative radiotherapy. Methods of cannabis product delivery were similar during adjuvant vs palliative radiation: edibles (75% vs 67%), liquids/tinctures (71% vs 83%), smoking (46% vs 47%), vaping (43% vs 43%), and pills/capsules/gel caps (18% vs 23%). Pain was the most common reason for using cannabis during adjuvant vs. palliative radiation treatment groups (77% vs 87%). Except for chronic pain (43% vs 67%, P < 0.05), no other pain subtype was statistically significantly different between adjuvant vs palliative care groups: acute pain (37% vs 47%), nerve pain (43% vs 57%), and joint/muscle aches/stiffness/pain (56% vs 60%). Pain was rarely the only reason for cannabis use, however. Other common symptoms for cannabis use during adjuvant vs palliative radiation included: insomnia (69% vs 77%), anxiety (58% vs 50%), stress (50% vs 43%), nausea/vomiting (47% vs 43%), and anorexia (38% vs 47%).

Conclusion: Almost half of all participants reported using cannabis during adjuvant or palliative radiation to relieve breast cancer symptoms or treatment side effects, most commonly: pain, insomnia, anxiety, stress, nausea/vomiting, and anorexia. Patients undergoing palliative radiation were more likely to use cannabis to relieve chronic pain compared to patients undergoing adjuvant radiation. Both oral and inhalational methods of cannabis delivery were commonly utilized, regardless of stage. Although preliminary research shows that cannabis helps to relieve pain, nausea, insomnia and anxiety, safety studies are needed regarding the use of inhalational cannabis products during breast radiation, given the known risk of pulmonary toxicity from cigarette smoking during breast radiation.