Survey measures cannabis use among cancer patients

About a quarter of cancer patients at MUSC Hollings Cancer Center report having used cannabis, or marijuana, since their diagnoses, a figure that is in line with estimates from states with legal marijuana access. Patients are most likely to use cannabis to help with sleep, pain, mood changes, stress, anxiety and depression.

The information is from a survey administered by Hollings researcher Erin McClure, Ph.D., as part of a larger look into cannabis use by cancer patients across the country. The National Cancer Institute awarded grants to 12 cancer centers to survey their patients. Researchers at the NCI are working on an overarching paper that compiles the results; McClure expects it may also explore some differences across cancer centers, particularly because the other 11 cancer centers are in states with legal marijuana access.

One aspect of the Hollings survey that stood out to her was the low number of patients who talked to their doctors about the fact that they were using cannabis.

“It will be interesting to compare that number for our site to states that have legal cannabis because I expect that there would be a much higher rate of conversation in states with legal marketplaces,” she said.

There is much that is unknown about cannabis use for cancer patients, although some early work indicates it may hinder the effectiveness of certain cancer treatments. But cancer patients at Hollings, whether they used cannabis or not, didn’t see the greatest risk to be to their treatment; instead, they perceived the greatest risk to be a legal one.

“One of the biggest risks that was noted for cannabis was the legal consequences associated with use. I think that probably prevents a lot of people in our state from initiating use even though they might be interested,” McClure said.

However, there is also the risk to treatment effectiveness.

“There is some preliminary data suggesting that people who use cannabis may have a worse treatment response to immunotherapy, so the concern is that using cannabis may be helpful for people in terms of sleep and pain, but it may be affecting their cancer treatment response,” McClure explained.

However, more work needs to happen to verify those findings, she said.

Because of the prevalence of cannabis use, the NCI is interested in investigating its effects from a number of angles, McClure said, including the therapeutic potential of cannabinoids and how it interacts with different types of cancer therapies.

McClure is hoping to conduct more research in South Carolina, including a naturalistic study that would follow patients for a year to measure their cannabis use and cancer outcomes.

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