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A Quarter of Cancer Patients Have Used Medical Marijuana

Where it's legal, at least.
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Approximately 40 percent of all Americans will develop cancer at some point in their lifetimes. And with the punishing chemotherapy, fatigue, and nausea that often follows some forms of treatment, nearly a quarter of cancer patients are turning to marijuana to help ease their symptoms, according to a new finding published in Cancer, a journal of the American Cancer Society.

As marijuana consumption gains acceptance, a growing number of cancer patients are starting to view the drug as a viable way to cope with their disease. Twenty-nine states and District of Columbia have passed regulations that allow various forms of medicinal or recreational marijuana. Yet patients who opt to use cannabis are largely stepping into a grey zone. "Cancer patients are hearing through different channels that it might be a benefit to them but there's almost no literature, no research to support that," says lead study author Steven Pergam, a clinical researcher at the University of Washington and the Fred Hutchinson Cancer Research Center in Seattle.


To get more data on the perceived benefits and frequency with which cancer patients were using marijuana, Pergam and his team surveyed 926 patients at the Seattle Cancer Center Alliance. They found that 66 percent of the patients had used marijuana for medical purposes at some point in the past. However, 24 percent of patients were "active users," meaning that they had used marijuana in the past year for cancer-related symptoms. Twenty-one percent had done so within the last month, and 18 percent within a week of their participation in the study.

But the researchers didn't just take patients' word for this. They also randomly tested patients' urine samples and found similar percentages of frequent users, based on the presence of tetrahydrocannabinol (THC), the chemical responsible for most of marijuana's effects. "This is a large number of patients using marijuana," Pergam says. However, there could be even more patients who hesitate to talk to their doctors about their marijuana use, he adds, particularly in states where it isn't legal or as accessible as Washington.

"What's really interesting is that almost three-quarters of patients really wanted to know more about medical marijuana, and they wanted to get that information from their doctors," Pergam says. But that wasn't where patients were getting their information. Most people sought out information from friends, relatives, and non-scientific sources online, according to the survey results.


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Most current users smoked or consumed marijuana primarily to alleviate their physical symptoms. Some patients said the drug helped ease pain and nausea, while others used it to help increase their appetite, which can change drastically during cancer treatment. Additional patients turned to cannabis to help cope with the stress of their treatment regimen, depression, and insomnia.

The problem, however, is that there is limited evidence and even fewer doctors trained to recommend cannabis as a treatment for cancer-related symptoms or cancer treatment-related symptoms. Previous research has reported mixed results for the effectiveness of marijuana in managing pain, and there have only been a few small studies regarding the effects of inhaled cannabis on appetite, mood, and anxiety.

The effects of marijuana can vary depending on whether it is inhaled or ingested. And the amounts of active chemicals can vary too, so there are concerns about the risks of taking the drug, especially in the already vulnerable physical state that most cancer patients are in, says Otis Brawley, chief medical officer of the American Cancer Society. "I would prefer that people use pills or liquid drugs because the dose of the chemical is very important, as is eliminating all the harmful chemicals in marijuana that may have their own side effects or carcinogenic properties," he says.

Currently, synthetic THC is the only chemical component of marijuana that is available in pill form as dronabinol, and is classified as a Schedule II drug. It is FDA approved and regularly prescribed by doctors to treat chemotherapy-caused nausea in patients who have failed to respond to conventional antiemetic therapy. But all other forms of marijuana should still be considered similar to over-the-counter supplements for now, Brawley says.

"We've got enough information to tell us that there are definitely some chemicals in marijuana that have medicinal properties. We also have a lot of information that tells us that there are definitely carcinogens in marijuana," he says. "Ideally what needs to be done is we need to get over the fact that it's marijuana, fund the research that needs to be done, and change the laws to allow the research to be done."

The new survey, published today, serves to highlight that cancer patients are curious about using marijuana for medicinal purposes and there's a dire need for more concrete scientific information so both patients and physicians can make well-informed treatment decisions, Pergam says. "We really need to open the lines of communication to find out if marijuana is right for cancer patients and to be able to advise patients properly."

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