Survey Sheds Light on Why Some Use Cannabis After Stem Cell Transplant

Nearly 20 percent of hematopoietic stem cell transplant (HSCT) survivors reported using cannabis, not just to ease physical and emotional side effects, but in the hopes that it would help treat their cancer, according to patient survey results presented at the 2018 of American Society of Clinical Oncology (ASCO) Annual Meeting.

The self-administered, 15-question survey was given between January 1 and June 1, 2017, to all adult survivors of HSCT at Fred Hutchinson Cancer Research Center in Seattle, Washington.

In total, 697 survivors — including 32 percent of eligible participants — completed the survey, and their answers were analyzed via descriptive statistics and logistic regression. The questionnaire was part of a larger annual survey of all the institution’s transplant survivors.

HSCTs treat people with blood cancers by replacing bone marrow that has been destroyed by cancer, chemotherapy or radiation with transplanted blood-forming cells, known as stem cells. Transplants come from a patient’s or donor’s bone marrow, peripheral blood or cord blood.

“Approximately 20 percent of cancer patients reported cannabis use within the last month, despite limited data regarding its risks/benefits,” wrote the authors of the study, led by Elizabeth Trice Loggers, M.D., Ph.D., medical director for palliative care at the Seattle Cancer Care Alliance and a sarcoma specialist. “More and more patients in the clinic were telling us that they were considering using, or already using, cannabis, and we wanted to understand how many were using and why,” Loggers, who is also an associate member of the Fred Hutchinson Cancer Research Center, added during an interview with CURE.

The researchers were particularly interested in use of the drug within the HSCT population.

“Most people are interested in using it because their perceptions are that it may help with physical symptoms such as pain, nausea, vomiting and insomnia, and these are common during transplant,” Loggers said. “Also, there are some concerns about the risks of using it during transplant due to potential respiratory infections of the lung with fungus or mold. Recently, some phase 2 studies showed there may be benefits of cannabis in preventing graft-versus-host disease. So, we’re interested in understanding this in our population.”

Of responders to the survey, 383 (55 percent) said they had no information about cannabis, 329 (47 percent) reported that they had considered using the drug and 124 (18 percent) had actually used it.

Reasons for considering cannabis use included physical symptoms (86 percent), emotional concerns (50 percent), recreation (45 percent) and to treat cancer (22 percent). Similarly, 22 percent were taking cannabis with the intention to treat graft-versus-host disease or other pre-existing conditions, Loggers said.

“The most common reason for considering and using cannabis was for management of physical symptoms such as pain and nausea, and (after that the most-reported reasons were) anxiety and stress reduction and recreation,” Loggers said. “We were very interested that 22 percent used it to treat cancer, for which there’s really no evidence.”

She added that “more than 80 percent of people using cannabis also understood that there were risks associated with its use.”

Those who submitted surveys were more likely to be older, white and female than patients who did not respond.

While HSCT survivors aged 18 to 39 years were four times more likely to consider using cannabis than those older than 65 years, age was not associated with actual use. Rather, use was associated with white race, perception of benefit, intention to treat cancer, and receipt of information about cannabis use from clinicians, naturopaths, cannabis dispensers or peers.

Cannabis use was not affected by the legal status of the substance in a patient’s state or province, the authors stated.

Loggers said the survey results point to the need for better communication between doctors and patients about the pros and cons of cannabis use.

“It was surprising that more than half of respondents didn’t have any information about cannabis, and among those who had information, most of it had come from family, friends and other cancer patients,” Loggers said. “Only one-third had spoken to doctors, nurses or nutritionists in the cancer center about it, but it’s important to do that, because there could be risks and we don’t know the effects of cannabis on their disease itself. We’re trying hard to communicate that it’s better to talk about it than not, regardless of whether they’re using. We want to know and talk about it freely.”

Also crucial will be larger studies of cannabis in these patients, she said.

“It would be important to repeat the study in a larger number of centers and see if it holds in different areas of the country,” where there are a variety of laws governing the use of cannabis, Loggers said. “There are also plans to study it in a rigorous scientific way for graft-versus-host disease prevention, and we may participate.”

“It’s remarkable how little is known about the risks and benefits of cannabis use,” she concluded. “We need more studies with respect to the risks, in a cancer transplant population, of cannabis increasing infections in the lungs, especially with fungus or mold — usually aspergillus. We’re concerned about drug interactions, addiction and use beyond the transplant period.”