Cancer patients who use cannabis receive insufficient information

Last Updated: 2017-09-25

By Will Boggs MD

NEW YORK (Reuters Health) - Many cancer patients use cannabis in states where it is legal, but most do not receive information about its use from their oncology providers, researchers report.

"I thought it interesting that many reported using cannabis to deal with stress, to cope with their illness, or for depression, and not just for physical symptoms," Dr. Steven A. Pergam from Fred Hutchinson Cancer Research Center, in Seattle, told Reuters Health by email. "At the same time, I was somewhat discouraged that despite a lack of scientific evidence, more than a quarter of patients actually thought that cannabis was helping to treat their cancer. In our minds, these data really indicate the need to better educate patients."

Cannabis is said to alleviate anorexia, nausea, and pain in cancer patients, but most available data on its medical use for these symptoms come from nonscientific observations.

During a 6-week period in 2015 to 2016, Dr. Pergam's team anonymously surveyed 926 cancer patients (median age, 58) in Washington State, which has legalized medical and recreational cannabis.

Overall, 66% of respondents had used cannabis at some point in their lives, and 24% considered themselves active cannabis users. Most active users (62%) had told their cancer team about their cannabis use, according to the September 25 online report in Cancer.

Three-quarters of active cannabis users reported using it at least once a week (moderate use), 56% using it at least daily (heavy use), and 31% using it multiple times a day.

Active users cited pain as the most common reason for marijuana use, followed by nausea/upset stomach and stress. More than a third (35%) used cannabis for enjoyment/recreation, but only 7.3% of that subset used it exclusively for that reason.

Just over a quarter of active users (26%) believed that cannabis was helping to treat their cancer, with 5% indicating that was the only reason for using it. Most patients (51%) felt that cannabis had a major benefit, 39% a moderate benefit.

Active users were more likely than prior users and never users to cite legalization as a factor in using cannabis, and women cited it more often than men.

Most respondents wanted to learn more about cannabis and cancer, but only 15% received such information from their cancer physician or nurse. Most received information from friends and family, newspaper and magazine articles, online, or another cancer patient. More than a third had not received any information.

"It is critical for clinicians to ask about cannabis use," Dr. Pergam said. "As cancer providers, we need to be willing to talk about this with our patients. If we aren't open to these discussions they will seek information from other sources and for some, put themselves at risk."

"Clinicians should be honest that we don't know a lot about the risks and benefits of cannabis in cancer care - that alone can help patients in making their decisions," he said. "We need more efforts to develop evidence-based training and tools to help clinicians become more comfortable discussing cannabis use with their patients."

"In those with very weakened immune systems, patients with leukemia or those undergoing a bone-marrow transplant, for example, I am much more cautious and actively discourage patient use because of the potential increased risk of fungal pneumonia," Dr. Pergam said. "That is in contrast to a patient in palliative care, where the benefits may outweigh the risks."

"It is important for patients to understand that not all cancers and treatments are the same, and that by discussing their use or their interest in cannabis with their providers, their cancer team can help them to make more-informed decisions," he concluded.

Dr. Gil Bar-Sela, head of supportive oncology at Rambam Health Care campus, Haifa, Israel, told Reuters Health by email, "Patients use cannabis. If physicians want it as a treatment tool for their patients, they should get more knowledge and ask the patients about cannabis use."

"For me, it was surprising to see the low percentage of patients that use cannabis daily (heavy users)," he said. "In order to get symptom relief, you need to use the cannabis on a daily basis and mostly more than one time/day because the cannabis influence lasts just for several hours."

Dr. Devan Kansagara from Oregon Health and Science University, in Portland, who has reviewed the effects of cannabis on chronic pain and posttraumatic stress disorder, told Reuters Health by email, "In a state in which cannabis is legal for recreational and medical purposes, a broad range of cancer patients of different ages and different backgrounds report using cannabis for a variety of physical and mental health symptoms."

"The key message for physicians is that patients are using cannabis and they want to talk to their health care teams about it, but relatively few report actually having had conversations about the pros and cons of use with their physicians," he said. "Even though the evidence base remains incomplete, we need to be more prepared to discuss cannabis with patients . . . (and) to have patient-centered discussions that take into account the evidence and patients' individual biopsychosocial circumstances."

SOURCE: http://bit.ly/2wh8wQ2

Cancer 2017.