Photo via the National Institutes of Health

Over the past two decades, the medical community has gradually come around to accepting that cannabis has a wide number of medical benefits. Research on the plant’s medicinal properties has increased dramatically in recent years, and there is now a substantial body of evidence supporting marijuana’s effectiveness as a treatment for epilepsy and as an alternative to opioid use.

But for other ailments, the medical powers of cannabis are less certain. Last year, the National Cancer Institute reported that several recent studies had found that cannabinoids had effectively killed cancer cells while protecting normal cells. These findings remain inconclusive, however, leaving most physicians specializing in cancer unsure about whether or not to recommend medical marijuana treatments.

A new study published in the Journal of Clinical Oncology reports that while many oncologists are willing to discuss and even recommend medical cannabis to patients, the majority of them feel that they don't have enough knowledge about the plant medicine to make solid clinical recommendations.

Researchers surveyed 237 oncologists around the country, asking about their beliefs, knowledge, and practices regarding medical marijuana. Only 30% of these doctors said they felt sufficiently informed to make confident clinical recommendations regarding medical cannabis and cancer. Regardless of this lack of understanding, around 80% of the doctors reported that they discussed cannabis treatments with their patients, and 46% still recommended these treatments.

Although there is a general understanding that cannabis can help cancer patients, oncologists debate exactly what symptoms the substance can actually treat. A third of the doctors surveyed were convinced that cannabis was more effective than traditional pain medication, another third felt that it was less effective, with the remaining third saying they simply didn’t know.

Ilana Braun, chief of Dana-Farber Cancer Institute's Division of Adult Psychosocial Oncology in Massachusetts and lead author of the study, told Wired that despite this uncertainty, there at least “seemed to be clear consensus that medical marijuana is a good adjunct to standard pain treatment, so a good add-on medication.”

The study also reported that most of the oncologists' discussions about medical marijuana were initiated by the patients themselves. Dr. Jerry Mitchell, medical oncologist at the Zangmeister Cancer Center in Ohio, told National Public Radio that medical marijuana is “well-known” as “a product cancer patients think will help them, and they're going to ask their doctors about it, which is what they should be doing. They should be advocates for their own health."

"Unfortunately, at this time, the evidence base to support medical marijuana's efficacy in oncology is young," Braun said to NPR. "So, often oncologists are borrowing from clinical trials for other diseases, or extrapolating from evidence on pharmaceutical-grade cannabinoids."

Oncologists' uncertainty about medical cannabis leaves it up to patients to figure out dosages and modalities of treatments on their own. Many cancer sufferers in states with medical marijuana programs have reported that doctors have told them they were eligible to use the drug, but could not provide any additional information on treatments.

Similarly, America’s veterans have remained in the dark regarding medical marijuana treatments for cancer — or any other condition — due to the Department of Veterans Affairs' strict anti-cannabis policies. VA doctors have been explicitly prohibited from recommending medical marijuana to veterans, again leaving it up to patients themselves to figure out how to best use cannabis medicine on their own.

The study concluded that there are “critical gaps in research, medical education, and policy regarding” medical marijuana. In order to resolve these concerns, controlled trials studying the effectiveness of specific cannabinoids on particular symptoms need to be undertaken, but federal prohibition of the drug continues to make such research exceptionally difficult.

Dr. Braun told NPR that she "strongly believes federal restrictions should be loosened to facilitate medical marijuana's potential beneficial attributes, not just its risks."