Oncologists uncomfortable prescribing medical marijuana despite benefit, study says

While 73 percent of surveyed oncology providers believe that medical marijuana provides benefits for cancer patients, only 46 percent are comfortable recommending it, according to new study by the University of Colorado Cancer Center.

Major concerns included uncertain dosing, limited knowledge of available products and where to get them, and possible interactions with other medications, the university said in a statement.

Survey respondents included 48 specialized oncologists, 47 physicians, 53 registered nurses, 17 pharmacists, and seven other oncology providers. Seventy-nine percent reported that educational programs both during training and as continuing medical education courses could increase their comfort level with medical marijuana prescribing. Additionally, 68 percent of providers reported receiving information about medical marijuana from their patients, with the next most common sources of information were news media (accessed by 55 percent of providers), and other providers (53 percent).

Providers also reported legal and regulatory concerns, especially providers working in academic medical centers who expressed uncertainty whether recommending medical marijuana could jeopardize federal funding. Marijuana remains a U.S. Drug Enforcement Agency Schedule 1 drug. Providers felt as if additional clinical data describing the effectiveness of medical marijuana and endorsed guidelines describing the conditions and situations in which it should be used would increase their comfort in prescribing.

The biggest issue, however, is that providers saw is the lack of certainty in dosing, according to Ashley Glode, PharmD, assistant professor at the Skaggs School of Pharmacy and Pharmaceutical Sciences and the study's first author.

"The issue is it's not regulated,” she said. “A dispensary might say a product has this much [tetrahydrocannabinol] (THC) and this much [cannabidiol] (CBD), but no one is testing that for sure.”

Limited data suggests that patients should start low and slow, no more than 10 milligrams of THC in a dose, but providers don't know that's what patients are really getting, Glode said. Then from a consumption perspective, inhalation and smoking is the least preferred due to possible damage to the lung. So many doctors recommend edibles, oils, and tinctures, but the medical community still does not have good data comparing dosage across these forms.

Glode says she and colleagues hope to expand the survey to gather a more nationally representative sample.

"Knowledge is an issue," Glode says. "If we could do a better job educating our healthcare providers, it might be used more often and potentially more safely."