Cancer patients are using marijuana to relieve a variety of symptoms. But even in states where it’s legal, patients are not getting the information they need.

About 25 percent of cancer patients use marijuana.

At least that appears to be the case in Washington, a state with legalized marijuana.

Washington legalized medical marijuana in 1998 and recreational marijuana in 2012. It’s been commercially available there since 2014.

With more than half of U.S. states now allowing medical marijuana, researchers wanted to determine how many cancer patients take advantage of the availability.

For the study, Dr. Steven Pergam of the Fred Hutchinson Cancer Research Center and his colleagues surveyed patients at the Seattle Cancer Center Alliance.

Of 2,737 eligible patients, 926 completed the anonymous survey.

Study authors acknowledge there might be some sampling bias due to the small response. They noted that it’s possible that current use patterns may be overrepresented or underrepresented.

Of those who responded, the median age was 58.

About 66 percent said they had previously used marijuana. About 24 percent used it in the past year and 21 percent in the past month.

Responses were validated by random urine samples.

The full study is published in the journal Cancer.

Dr. Junella Chin is an osteopath and integrative cannabis physician.

She has practiced in California and New York, two states that have legalized medical marijuana.

“There is an absolute increase in states where it has been legalized. I have seen this in California over the last decade, and now in New York City,” she told Healthline.

Chin said there’s been a surge of patients registered in the New York State Medical Marijuana Program.

“What is not typical about my practice is that even among the limited number of doctors who are performing medical cannabis evaluations, I am one of the few who does them in the context of a full-scope general medical practice,” said Chin.

“I have worked to develop my own standards by reading the scientific literature, learning from the experience of other expert clinicians and international scientists, and thorough application of the past 15-plus years of treating patients,” she explained.

Most of the study respondents said they used marijuana for physical and psychological symptoms.

Reasons included pain, nausea, upset stomach, and stress.

Some also reported using it for enjoyment.

Sometimes cancer patients simply run out of options, said Chin.

They’re given a variety of medications to combat symptoms and side effects.

“And when these don’t work, or they are too taxing on their system, they research cannabis as an option, legal or not,” she said.

According to Chin, cannabis is the only anti-nausea medicine that increases appetite, helps patients sleep, eases pain, and elevates mood.

Study authors point to the need for clinical trials to evaluate the role of cannabis in symptom management.

Marine Yanikian-Sutton, 39, was diagnosed with colon cancer in 2016.

Yanikian-Sutton, who is now in remission, told Healthline that she used marijuana while undergoing chemotherapy.

“It eased both mental and physical pain, and I could not have endured the pain without it,” she said.

Although it’s legal in her state, Yanikian-Sutton said that wasn’t a deciding factor.

“The deciding factor was the realization that the chemo meds are more poisonous and life threatening than the marijuana. I chose to ease the side effects produced by the chemo naturally, as opposed to taking more meds,” she said.

She didn’t take this step lightly.

“I researched it, discussed it with my oncologist, received sound advice as to which [strains] to use to ease which symptoms before I obtained the license necessary to purchase it,” she explained.

“In California, there are organizations that provide free marijuana to cancer patients, and I was one such patient,” added Yanikian-Sutton.

About 70 percent of study respondents who use cannabis reported inhaling or consuming it in food. About 89 percent used both methods.

Chin said patients are using tincture (sublingual), capsules, and vape.

“It depends on preference and/or the reasons why it’s being used. For example, vape is great for nausea. It takes away nausea within minutes. Patients may use sublingual [applied under the tongue] for sleep or pain, for an even longer extended relief. But the onset of action might be 30 minutes to one hour,” explained Chin.

All cannabis is not the same.

Chin pointed out that there’s a huge variation in cannabis medicine. And strain names can be misleading.

“With the new state regulations, there will hopefully be a system in place in which the consumer can get the biochemical compound of the plant/product,” she said.

As for cancer patients who live in states without legalized cannabis, Chin said, “I caution obtaining unregulated cannabis because it passes six hands before it gets to you. If you areimmunocompromised, you can’t risk using cannabis that is contaminated with fungus, pesticides, etc.”

Study authors found that legalization was an important factor in the decision to use cannabis.

They concluded that cancer patients in a state with legalized cannabis had high rates of active use across broad subgroups.

They also noted that cancer patients would prefer to get information about cannabis from their oncologist.

But that’s not happening.

“We hope that this study helps to open up the door for more studies aimed at evaluating the risks and benefits of marijuana in this population. This is important, because if we do not educate our patients about marijuana, they will continue to get their information elsewhere,” Pergam said in a press release.

Chin agrees.

“Many doctors are not educated on the endocannabinoid system. I certainly was not, and I attended medical school and did my residency in California, a state that legalized it in 1996,” said Chin.

“Doctors may not be comfortable recommending or following up with patients on cannabis, so they refer to me,” she continued.

She’d like to see the chemical composition of cannabis medicine on detailed labels, much like food labels.

“The trouble is,” said Chin, “we are still dealing with a clandestine industry. The states that have set forth regulation and legalized medical cannabis model should also be actively educating patients about cannabis medicine.”

“More educated patients will come to understand the source and quality of medicine and work with their doctor on how cannabis can help them with their life-threatening disease,” said Chin.