Oncologists often suggest medical marijuana, but know little about it, survey finds

Oncologists admit they don’t know much about how marijuana might affect their patients. But a new national survey shows that nearly half prescribe it anyway.

“The majority feel like it has medical utility for some indications,” said Dr. Ilana Braun, chief of the division of adult psychosocial oncology at the Dana-Farber Cancer Institute in Boston, who led the new research.

As an oncologist, Braun said, she hears a growing number of her own patients asking about medical marijuana. “I occasionally recommend it, but very carefully and it’s on an individual patient basis,” she said.

There have been no gold-standard clinical trials of marijuana in cancer patients, according to the study, and not much research overall into the possible medical benefits of marijuana, because the U.S. government stopped funding medical marijuana research decades ago.

Studies do support marijuana use among cancer patients suffering from chemo-induced nausea and vomiting, and chronic pain related to neuropathy, said Stephen Corn, an anesthesiologist who educates doctors on medical marijuana.

Less-rigorous evidence suggests it may help cancer patients who have trouble sleeping, feel anxious, suffer from poor appetite, or seek a substitute for opioid painkillers.

Twenty-nine states now allow people access to marijuana for a range of medical conditions including cancer. The federal government, however, continues to consider it a drug of addiction, like heroin, and restricts both its use and funding research into it.

For the new study, researchers mailed a survey to 400 randomly selected oncologists across the country, both in states that allow medical marijuana and those that prohibit it. Among the 237 doctors who responded, 80 percent said they have talked to their patients about medical marijuana and 46 percent said they have recommended it, mainly for pain and unintentional weight loss. But only 30 percent of oncologists “felt sufficiently informed to make recommendations” regarding medical marijuana, according to the survey, published in the Journal of Clinical Oncology.

The new survey is the first in decades to ask oncologists their views on medical marijuana.

Three-quarters of those surveyed also thought marijuana was less likely than opioids to lead to overdose, and half thought it was less likely to lead to addiction. In one recent Israeli study, elderly cancer patients overwhelmingly said medical marijuana helped them with pain, and 18 percent were able to reduce or eliminate their use of opioids.

A lot of the medical interest in marijuana has been driven by patients, Braun and Corn agreed. In another survey published last year by Seattle researchers, three-quarters of relatively young cancer patients said they wanted more information about cannabis, and about one in five had used it in the last month.

It’s not surprising that doctors don’t know much about cannabis, Corn said. They are never taught in medical school, not just about the drug, but about the body’s so-called cannabinoid system, which affects a wide range of bodily functions including mood, temperature control, appetite, sleep, and balance, he said. His website, TheAnswerPage.com, which he runs with his wife, Meredith Fisher-Corn, also an anesthesiologist, provides continuing medical education content for doctors on the subject.

“A relatively small percentage of doctors are being educated on medical cannabis,” Stephen Corn said.

Braun said she would recommend that her patients get their cannabis from a medical marijuana dispensary, rather than an outlet that caters to recreational users. There’s no evidence to say whether recreational marijuana is just as safe and useful for cancer patients as the more expensive medical-grade variety, though some dispensaries take extra care to ensure there are no pesticides or mold in their medical-grade cannabis.

Dr. Donald Abrams, an oncologist at the University of California, San Francisco, said he finds medical marijuana effectively addresses a wide range of patient complaints. “A day doesn’t go by that I don’t see a cancer patient that doesn’t have nausea, pain, depression, and insomnia,” he said. “I can recommend that they try one therapy, [marijuana], as opposed to six or seven different medications that may all interact with each other or the chemotherapy that I’m prescribing. “

Abrams conceded that it can be challenging for patients to figure out exactly what kind of medical marijuana to use and how much.

Doctors treating a patient with mood disorders might prescribe 50 mg of Zoloft to be taken at night. But with marijuana, Abrams said, the medical recommendation is more akin to: choose for yourself between Zoloft, Prozac, and Wellbutrin at whatever dose and time of day you think is appropriate.

Patients with questions should ask for advice from “bud-tenders” at marijuana dispensaries, he said, noting that cannabis can be smoked, vaporized, rubbed on, or eaten in a variety of forms.

Abrams said doctors will probably never have the same level of information on medical marijuana that they have on most prescription medications. But, he says, that shouldn’t stop people from using it.

“I don’t think we’re ever going to pharmaceuticalize the plant, but it’s been a remedy for the last 3,000 years, so people can figure out how to use on their own without a package insert,” he said.