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New studies support cannabis as complementary cancer treatment

New research finds cannabis can help relieve pain, reduce the use of other pharmaceuticals and improve sleep in cancer patients.



Researchers say medicinal cannabis can safely relieve cancer pain, while curbing the consumption of opioids.

New research has found that cannabis can help relieve pain, reduce the use of other pharmaceuticals and improve sleep, when used as a complementary therapy in cancer patients. 

The results of a multi-centre registry study, published online in BMJ Supportive & Palliative Care, suggest that medicinal cannabis can safely relieve cancer pain, while curbing the consumption of opioids and other pharmaceuticals among patients. 

Overall, THC:CBD balanced products were associated with better pain relief than either THC-dominant or CBD-dominant ones.

The findings have prompted researchers to conclude that medicinal cannabis is a safe and complementary treatment when conventional drugs fail to effectively relieve cancer pain.

Over half of patients undergoing anticancer treatment and two thirds of those with advanced or terminal disease experience pain, say the researchers.

This is usually treated with opioids and other medications, such as anti-inflammatory and anticonvulsant drugs. But one in three patients will still experience pain, added to which the side effects of opioids include nausea, sleepiness, constipation, and respiratory depression, point out the researchers.

Reductions in pain and opioid use

Researchers studied the treatment responses of 358 adults with cancer whose details were submitted to a multi-centre registry—the Quebec Cannabis Registry in Canada—from May 2015 to October 2018.

The three most common cancer diagnoses were genitourinary, breast, and bowel. Pain was the most frequently reported (72.5%) symptom for which medicinal cannabis was prescribed.

THC-dominant, THC:CBD-balanced, and CBD-dominant products were authorised in 24.5%, 38%, and 16.5% of patients, respectively. Taking the product by mouth was the most frequently recommended route in 59% of cases. 

Patients’ pain intensity, symptoms, total number of drugs taken, and daily morphine consumption were monitored quarterly for one year.

Statistically significant decreases were observed at three, six and nine months for worst and average pain intensity, overall pain severity, and pain interference with daily life.

The total number of drugs taken also fell consistently at all the subsequent quarterly check-ups, while opioid use fell over the first three check-ups.

Medicinal cannabis seemed to be safe and well tolerated, with only 15 moderate to severe side effects reported by 11 patients, 13 of which were regarded as minor. The two most common side effects were sleepiness, reported by three patients, and fatigue, reported by two. 

“The particularly good safety profile of [medicinal cannabis] found in this study can be partly attributed to the close supervision by healthcare professionals who authorised, directed, and monitored [the] treatment,” highlight the researchers.

The authors conclude: “Our data suggest a role for [medicinal cannabis] as a safe and complementary treatment option in patients with cancer failing to reach adequate pain relief through conventional analgesics, such as opioids.”

Smaller study finds improvements in cognition 

A separate smaller study from the University of Colorado Boulder also found that cancer patients who used cannabis to treat their symptoms had less pain and slept better. After a few weeks of sustained use, they also reported less brain fog and could think more clearly.

Researchers collaborated with oncologists at the CU Anschutz Medical Campus to observe 25 cancer patients who used cannabis over two weeks. 

After a baseline appointment in which their pain levels, sleep patterns and cognition were assessed, they were asked to purchase the edible product of their choosing from a dispensary. Choices were surprisingly varied, spanning 18 brands, including chocolates, gummies, tinctures, pills, and baked goods, and contained varying ratios of THC and CBD at a wide range of potencies. 

After two weeks of sustained use, patients reported improvements in pain, sleep quality and cognitive function. Some objective measures of cognitive function, including reaction times, also improved.

“We thought we might see some problems with cognitive function,” said Bryan, noting that both cannabis and chemotherapy have been previously associated with impaired thinking. 

“But people actually felt like they were thinking more clearly.”

The more people’s pain subsided, the more their cognition seemed to improve.

Those who ingested more CBD, a known anti-inflammatory, reported bigger improvements in sleep quality and pain intensity. 

While larger controlled studies are needed, the authors say the findings suggest that while some forms and dosages of cannabis for pain relief may impair thinking in the short-term, some regimens might improve cognition in the long run by reducing pain.

Sarah Sinclair is a respected cannabis journalist writing on subjects related to science, medicine, research, health and wellness. She is managing editor of Cannabis Health, the UK’s leading title covering medical cannabis and CBD, and sister titles, Cannabis Wealth and Psychedelic Health. Sarah has an NCTJ journalism qualification and an MA in Journalism from the University of Sunderland. Sarah has over six years experience working on newspapers, magazines and digital-first titles, the last two of which have been in the cannabis sector. She has also completed training through the Medical Cannabis Clinicians Society securing a certificate in Medical Cannabis Explained. She is a member of PLEA’s (Patient-Led Engagement for Access) advisory board, has hosted several webinars on cannabis and women's health and has moderated at industry events such as Cannabis Europa. Sarah Sinclair is the editor of Cannabis Health. Got a story? Email / Follow us on Twitter: @CannabisHNews / Instagram: @cannabishealthmag


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