An accompanying editorial questioned whether the rush to decriminalize marijuana for medicinal use was putting getting ahead of itself and urged additional research.3

“It has been argued that the lack of high-quality evidence reflects the difficulty in conducting marijuana research in the United States,” the authors wrote. “If so, the federal and state governments should support and encourage such research so that high-quality evidence can be generated to guide decisions about medical marijuana use for the conditions for which the existing evidence is either insufficient or of poor quality.”

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The newer review aimed to focus specifically on the research into the benefits and risks of marijuana for cancer patients.

“In oncology we have a lot more patients asking for it both for treatment and for symptoms and there just wasn’t a lot out there,” Rizack said. “There wasn’t 1 summary just for oncology patients, looking at their specific issues.”

They found that even though 23 states and the District of Columbia have laws legalizing marijuana use in some form, and access to medical marijuana is increasing, “there just isn’t a lot of research,” she said.

Among the challenges for researchers, she said, is the nature of marijuana itself.

Generally in clinical trials, she said, “When we compare drugs to other drugs, or to a placebo, that’s something in a known quantity with a known effect. Medical marijuana is something that when it’s used it’s not always a controlled dosage. It’s not always the same kind of plant. It’s hard to do a controlled study because there are so many confounders.”

RELATED: Patients with Cancer Use Medical Marijuana to Relieve Severe Symptoms, Side Effects

One outcome of the review she said she hopes for is that it will call attention to the lack of hard data and “maybe stimulate a little more research.”

“I think there may definitely be a role in patients who have refractory nausea and for patients that are in pain, and that there is a potential role for use as a therapeutic use for cancer treatment,” she said, “but that might be down the pipeline a few years. I think we definitely need more information.”


  1. Wilkie G, Sakr B, Rizack T. Medical marijuana use in oncology, a review [published online ahead of print March 17, 2016]. JAMA Oncol. doi:10.1001/jamaoncol.2016.0155.
  2. Whiting PF, Wolff RF, Deshpande S, et al. Cannabinoids for medical use, a systematic review and meta-analysis, JAMA. 2015;313(24):2456-2473.
  3. D’Souza DC, Ranganathan M. Medical marijuana: is the cart before the horse? JAMA. 2015;313(24):2431-2432.