A new study conducted in a cancer center in a state with legalized medicinal and recreational marijuana found that approximately one-quarter of surveyed patients used marijuana in the past year, mostly for physical and psychological symptoms. Published early online in CANCER, a peer-reviewed journal of the American Cancer Society, the study also revealed that legalization increased the likelihood for use among patients.

Eight states and the District of Columbia have legalized recreational marijuana, and over half the states in the U.S. have passed laws allowing for medical marijuana in some form. As availability and acceptance of marijuana use continue to increase, many cancer patients will have greater access to marijuana during their cancer treatment.

Marijuana is purported to alleviate symptoms related to cancer treatment, but patterns of use among cancer patients are not well known. To investigate, Steven Pergam, MD, MPH, of the Fred Hutchinson Cancer Research Center and his colleagues surveyed 926 patients at the Seattle Cancer Center Alliance.

The team found that most patients had a strong interest in learning about marijuana during treatment and 74 percent wanted information from cancer care providers. Sixty-six percent had used marijuana in the past, 24 percent used in the last year, and 21 percent used in the last month. Most current users smoked or consumed marijuana primarily for physical symptoms (such as pain and nausea) or psychological reasons (such as coping with stress, depression, and insomnia).

The study reports that random analysis of patient urine samples showed that 14 percent had evidence of recent cannabis use, similar to the 18 percent of users who reported use within the past week.

Although nearly all respondents wanted more information directly from their doctors, most reported that they were more likely to get information from sources outside of the healthcare system. "Cancer patients desire but are not receiving information from their cancer doctors about marijuana use during their treatment, so many of them are seeking information from alternate non-scientific sources," said Dr. Pergam. He stressed that marijuana may be dangerous for some cancer patients or lead to unwanted side effects. "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."