Even as an increasing number of states approve the use of medical marijuana, a review of medical literature and existing data finds that huge questions remain about its true benefits and risks for patients with cancer.1

Investigators found that despite centuries of medical and recreational use, and its potential benefits as an antiemetic, as a palliative for refractory cancer pain, and as an antitumor agent, “much of the data are based on animal data, small trials, or are outdated.”

The authors of the review, which was published in JAMA Oncology, looked at the history and legal status of marijuana use, its mechanism of action, and past studies of its antiemetic effects with chemotherapy-induced nausea and vomiting, in alleviating cancer-associated pain, and as an antitumor agent.

The review’s corresponding author, Tina Rizack, MD, with the Program in Women’s Oncology, Women and Infants’ Hospital, Alpert Medical School of Brown University in Providence, RI, told Cancer Therapy Advisor that the goal was to provide “a resource for oncologists to look at to answer their patients’ questions.”

A broader review and meta-analysis looked at randomized trials examining effects on nausea and vomiting caused by chemotherapy, appetite stimulation in HIV/AIDS cases, chronic pain, spasticity due to multiple sclerosis or paraplegia, depression, anxiety disorder, sleep disorder, psychosis, glaucoma, or Tourette syndrome.2

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It included a total of 79 trials involving 6462 participants. While most trials “showed improvement in symptoms,” the review concluded, they “did not reach statistical significance in all trials.”

It found “moderate-quality evidence to support the use of cannabinoids for the treatment of chronic pain and spasticity,” but only “low-quality evidence” supporting its use for the other indications, including its use for chemotherapy-associated nausea and vomiting.