New survey to understand the prevalence of marijuana use among cancer patients

Marijuana use is illegal in South Carolina, even for medical purposes. But national survey data shows that the use of marijuana for medical reasons is common, regardless of whether the people who use it live in a state with a legal marketplace.

To understand the prevalence of marijuana use among patients receiving care at MUSC Hollings Cancer Center, researchers have been awarded a $150,000 grant from the National Cancer Institute (NCI) to conduct a one-time survey of patients about their marijuana use. The grant was awarded as an administrative supplement to Hollings' NCI Cancer Center Support Grant, which aids the center's mission as an NCI-designated cancer center.

Led by Hollings Cancer Center researcher Erin McClure, Ph.D., an associate professor of Psychiatry and Behavioral Sciences at the Medical University of South Carolina, the project aims to characterize marijuana use in terms of how often patients are using it, why they're using it and the perceptions or beliefs they have about its efficacy in managing their cancer or other medical symptoms. The survey will also look at the types of products patients are using in terms of their formulation and potency.

McClure hopes the information obtained through the survey will offer insight to providers both at Hollings and across South Carolina, as there is currently limited data to show the prevalence and specific details about marijuana use among cancer patients in the state.

There are a few studies that have looked at cannabis use among cancer patients and found that use is pretty common. But these studies tend to take place in states where there's a legal, recreational or medical cannabis market. We don't have that in South Carolina, and we don't have a ton of information about whether our patients are using it medically, what they're using it for, and if they're using it in place of other medications."

Erin McClure, Ph.D., Associate Professor of Psychiatry and Behavioral Sciences, Medical University of South Carolina

A shift in perception

According to McClure, marijuana use in cancer patients may be common because of the symptoms the substance is touted to treat. Many people find that marijuana can help them to manage pain, reduce anxiety and depression, eliminate nausea and improve appetite and sleep, but there is limited scientific data to support conclusively whether those claims are true.

In addition, the perception of marijuana has shifted in the past several decades. Many people feel that it's much less harmful than it used to be and that it can be helpful for people with certain medical conditions.

"When you combine the expectation that cannabis can be beneficial for managing symptoms with the reduced perception of harm, I think that has contributed a lot to the increase in use," said McClure. "I expect the people who are using cannabis medically probably feel that it's safe for them, and they may feel that it's safer than other medications they're taking. They may also experience fewer side effects from cannabis than with other treatments. I think it comes down to the fact that people use it because they feel that it works for them."

The survey will ask participants about their perceptions of marijuana, regardless of whether they are using it. The researchers are curious to see if perceptions among nonusers differ from those who are using it to manage symptoms. The survey will also ask participants if those perceptions would change if medical or recreational marijuana became legal in South Carolina.

The survey will be distributed to people who have been treated at Hollings for their cancer diagnosis in the last two to three years. The researchers hope to enroll 1,000 patients by the middle of 2021 to provide them with enough data to dive deep into how and why marijuana is being used. The findings will be shared with the scientific and medical communities and also presented to providers at Hollings and across MUSC to give them a better idea of marijuana use among their patients.

Breaking the silence

McClure admits there's still a lot that is unknown about medical marijuana use, not just in treating specific medical conditions, but in terms of its safety and efficacy. Part of the reason for the unknowns is because marijuana is not commonly discussed, even in medical settings.

"Cannabis use is generally not asked about as part of patient care. I think people are sometimes hesitant to talk about it because it's an illegal substance in this state, so they may not want to admit they're using it. By asking about cannabis in a research context and by not entering any of this information into medical records, we hope that people will be honest about their use," said McClure.

While marijuana is generally perceived as being relatively safe for adults and has few interactions with other medications or treatments, there are some dangers associated with regular use. In adults, a common problem is developing a dependence. In youth, some studies have pointed to issues with neurodevelopment, memory and attention.

Part of the problem in figuring out its safety stems from challenges in determining how much use is problematic. For people who use it recreationally, using it several times per day could cause problems in their daily lives. But for people who use it just as often for medical purposes, it may be the only thing preserving their ability to function normally, she explained. Thus, its safety may vary among individuals based on their specific circumstances and how they are using marijuana.

The researchers expect 10% to 15% of their survey participants to be users of marijuana. The data collected will allow the researchers to look for trends based on age, gender, race, ethnicity, cancer type and even by the type of treatment patients have received. They hope the results will offer providers another tool for openly discussing marijuana use with their patients, which might also give them a chance to address any symptoms for which patients may be using marijuana to cope.

"My hope is that this information will open up a dialogue between the provider and the patient or provide them with some talking points for patients around cannabis use. I think some providers may not address cannabis use because they're not really sure what advice to give. Even if they feel it could be useful for the patient, it's still illegal in our state, so they may not feel comfortable recommending it," explained McClure. "I think it's important for us to understand cannabis use among these patients, especially in states where we don't have a legal marketplace. I'm glad the NCI finds this topic important and decided to support this study."