Medical Cannabis Can Treat Cancer Pain, Study Finds

Medical cannabis products can help relieve cancer pain and curb a patient’s need for other medicines and opioids, a new study suggests.

Published in the journal BMJ Supportive & Palliative Care, the study analyzed data collected from patients with cancer who were a part of the Quebec Cannabis Registry. The researchers found that patients’ ratings of average pain severity, worst pain severity, and pain interference all fell after starting medical cannabis treatment.

The researchers also found that medical cannabis helped to reduce the total number of other medications and opioids that patients reported using. Based on this evidence, the researchers say that medical cannabis could be a “safe and complementary treatment option” for those suffering from cancer-related pain.

Medical cannabis provides pain relief

Approximately 55% of cancer patients experience pain when undergoing anticancer treatment, with 66% of individuals with advanced or terminal cancer also frequently reporting pain symptoms. Opioid medications are commonly prescribed to help combat this pain, however these medications can have unpleasant side effects and are often unsuitable for long-term use. Furthermore, around one-third of those with cancer pain report that these opioid medications still do not provide sufficient pain relief.

While current research on the topic is somewhat spilt, recent reviews have suggested that cannabis can be beneficial to those suffering from pain conditions such as neuropathic or rheumatic pain, headache, and multiple sclerosis-related pain.

To determine the safety and efficacy of cannabis as an adjunct treatment for cancer-related pain, the researchers behind this latest study examined data collected from patients with cancer who were receiving cannabis through the Quebec Cannabis Registry between 2015 and 2018.

A total of 358 patients were eligible for inclusion in the study. All patients listed pain as one of their symptoms, with pain being the primary indication for cannabis use in 74% of the study group. Each participant attended a baseline appointment and follow-up appointments at 3, 6, 9, and 12-months from the original appointment. At these visits, patients were assessed by physicians and answered questions from two validated pain surveys, the Brief Pain Inventory (BPI) and revised Edmonton Symptom Assessment System (ESAS-r) questionnaires.

The researchers found that there was a statistically significant decrease in the BPI measures for worst pain, average pain severity, and pain interference in daily life over the study period. Pain severity as measured by the ESAS-r also fell when comparing the numbers reported in the follow-up appointments to baseline levels.

Balanced cannabinoid levels prove most effective

The researchers were also able to access data describing the different types of medical cannabis product that each patient had been prescribed. They found that THC-dominant, THC:CBD-balanced, and CBD-dominant products had been authorized for 24.5%, 38%, and 16.5% of patients respectively.

When cross-referencing this with the pain data, the researchers noted that the THC:CBD balanced products were generally more effective for pain relief than the other two product types.

In addition, the patients were asked to report their use of other medications and opioids at baseline and at each of the follow-up appointments. From this, the researchers calculated each patient’s total medication burden (TMB) and morphine equivalent daily dose (MEDD) at each timestep.

By the 12-month follow-up, the researchers observed a statistically significant decrease in total medication burden in around 32% of the participants. Decreases in MEDD were also seen in 14% of the patients by the 12-month mark.

Based on these data, the researchers say that adjunct medical cannabis treatment with balanced THC:CBD products could help to reduce other medication use in addition to reducing pain for patients.

Real-world data shows the safety of cannabis

Crucially, the adjunct medical cannabis treatments appeared to be safe and very well tolerated among the study participants. Across the entire course of the study, just 15 adverse events were reported.

Thirteen of these were categorized as being “non-serious” adverse events, such as drowsiness or fatigue. The two serious adverse events – one report of pneumonia and one cardiovascular event – were determined to be unrelated to the individual’s participation in this cannabis study.

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

“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.”

Due to the study’s observational nature, the researchers cannot explicitly confirm that any reductions in pain or other medication use were caused directly by the medical cannabis treatment. They also note that a significant number of patients were lost to follow-up as the study progressed. However, based on the observations made, they say that further randomized placebo-controlled trials investigating the use of cannabis for cancer pain are warranted.