A significant proportion of cancer patients are using complementary and alternative medicines (CAM) including medicinal cannabis and magnesium, an Australian study has shown.

In a survey of 104 patients attending the Day Oncology Unit of the Townsville University Hospital for mainly breast, lung and prostate cancer, 40% reported using CAM. Most (89%) had received chemotherapy, 40% had received radiotherapy and 30% had received surgery.

The findings, published in Complementary Therapies in Medicine, showed the most commonly used therapies were cannabis (27 %), magnesium (24%) and massage (20%), with the average CAM user utilising at least two CAM modalities.

Over half of CAM users stated that they used CAM to reduce their symptoms or the side effects of their medical treatment (58%), to improve their general health (58%), or to treat their cancer (50%).

However, quality-of-life as assessed by the FACT-G questionnaire found no significant differences between CAM users and non-users overall or on most domains except that non-users had higher emotional wellbeing scores than CAM users.

Most (68%) had disclosed their CAM use to a health professional for a professional opinion (67%) or due to concern about potential interactions with their cancer therapy (44%).

The survey revealed CAM users were more likely to have used CAM prior to their diagnosis.

They typically relied on CAM recommendations from friends and family (21%) or personal motivation (19%), while most information on CAM was sourced from the internet (20%).

“Given the extent of patients seeking recommendations for CAM use from outside the healthcare system, it does highlight that cancer patients may not be seeking advice from reputable health information sources.”

Non-CAM users said they either did not have knowledge of CAM (44%) or were concerned CAM may interact with their cancer treatment (34%).

“This shows that the safety of CAM use with conventional treatment is an important concern of CAM users and non-users, confirming a role for oncology health professionals in providing information on the safety of CAMs in cancer care,” the study investigators said.

Most evidence for cannabis was low quality, even for the common indication of chemotherapy-induced nausea and vomiting, they noted.

“Additionally, the various dosage forms of cannabis that can be obtained as well as the different cannabinoids that may be present in these products, increase the variability in this CAM and consequently the difficulty for an oncology health professional to advise when combined with conventional cancer treatment.”

They concluded that continuing education on CAMs for oncology health professionals was important to allow them to have informed conversations with their patients.

“This would, in turn, encourage patients to view their treating team as a source of information about these therapies and encourage disclosure of CAM use by cancer patients, resulting in safe and holistic treatment outcomes for this population group.”

Medical cannabis unmonitored

Meanwhile, an unrelated Commentary article on medicinal cannabis has said there is a need for processes to enable the systematic monitoring of patient outcomes in Australia.

The article, published in the International Journal of Environmental Research and Public Health, said medicinal cannabis prescribing has increased by more than 200% per month during 2017-2022.

Most approvals were for chronic pain (58%) and anxiety (23%) rather than cancer pain and symptoms management (4%).

It said most adverse effects of medicinal cannabis appear to be manageable and short-lived.

“However, the long-term effects of medicinal cannabis remain unknown and will continue to be poorly understood until signals of longer-term effects are detected.”

“Ongoing and rigorous monitoring is especially important given that the introduction of medicinal cannabis prescribing into “pharma” was not underpinned by research evidence from clinical trials (as is the usual process for TGA-regulated drugs),” it said.

It said a patient registry for the monitoring of medicinal cannabis effect and adverse events, the use of patient-reported outcomes and digital tools such as smartphone apps could be considered. ,

“The capture of more highly granulated data, such as found in an established registry, would provide the opportunity to monitor product effectiveness and safety across indications and would be especially useful when incorporated with input from prescribers, practitioners, and consumers.”