Cannabis in Palliative Care: What the Research Says About Cancer Pain

Cannabis is often used in palliative care to ease pain, anxiety, poor appetite and sleep problems in people with serious or terminal illness, and many patients report it helps. But when it comes to cancer pain specifically, a major review of 14 clinical trials found that cannabis-based medicines didn't relieve pain significantly better than a placebo. Here's what that research looked at and what it actually found.

Interest in cannabis as a palliative option keeps growing because of how many symptoms it's linked to: patients and doctors point to pain relief, less anxiety, better appetite and better sleep. The question is how much of that holds up when you put it to a rigorous test, and the answer, for now, is more mixed than the hype suggests.

Cannabinoids, the active compounds in cannabis, interact with the body's endocannabinoid system, which may help manage some of the symptoms that come with serious illness. With that in mind, let's look at what the evidence says about cannabis as a source of relief and comfort in palliative care, and where its real potential lies.

Does cannabis oil help with cancer pain?

Cancer pain is a major concern for people living with the disease, and it takes a toll on quality of life and overall well-being. The World Health Organization (WHO) recommends opioids, like morphine-type drugs, for moderate to severe cancer pain. Even so, somewhere between one in ten and one in six people don't get enough pain relief from these standard treatments.

Background: why researchers looked at cannabis

Looking for effective alternatives, researchers have explored cannabis-based products for cancer pain. These include cannabis inhaled or taken by mouth, plus various oils, sprays and pills containing active ingredients either extracted from the plant or made synthetically. Some people say cannabis medicines bring them relief, but it's crucial to test how well they work, and how safe they are, in a systematic way.

What the review set out to answer

The main goal of this review was to find out whether cannabis-based medicines relieve pain in people with cancer, and whether they cause any unwanted or harmful effects.

How the review was done

Researchers ran a thorough review of clinical trials comparing cannabis-based medicines with other treatments for cancer pain in adults. They pooled the results and rated how much confidence the evidence deserves, looking at factors like study design and size.

What they found

They identified 14 studies involving 1,823 people, with different treatment lengths and doses. Most of the studies were done in North America, and several were funded by pharmaceutical companies.

The medicines tested included both plant-derived THC and CBD products and synthetic cannabinoids that mimic THC. None of the studies used the cannabis plant itself.

The takeaway

This review gives a broad look at how effective and safe cannabis-based medicines are for cancer pain. The results make it clear that more research is needed to understand their role and whether they belong in pain management for cancer patients.

Cannabis medicines for cancer pain: the key results

Does a THC and CBD mouth spray work?

A mouth spray combining plant-derived THC and CBD didn't significantly reduce moderate to severe cancer pain compared with a placebo, in people who were already on opioids.

In the data, about 32% of people using the cannabis spray reported meaningful improvement, compared with 23% of those on the placebo spray.

The cannabis spray also had a 19% dropout rate, slightly higher than the 16% seen with the placebo spray. There was no significant difference in serious side effects between the two groups.

Does synthetic THC help with chemo-related pain?

A synthetic cannabinoid that mimics THC was no more effective than placebo at reducing pain from chemotherapy or chemoradiotherapy in people with head and neck cancer and certain types of lung cancer.

How does it compare to a morphine-type drug?

In people who had stopped their previous painkillers, a single dose of a synthetic THC-like cannabinoid didn't reduce moderate to severe cancer pain any more than a single small dose of a morphine-type drug, over a period of three to four and a half hours.

Does CBD oil help with pain in palliative care?

Based on the only study available, adding CBD to standard palliative care doesn't seem to provide any extra pain relief for people with advanced cancer.

Limits of the evidence

There's moderate confidence in the finding that a THC and CBD mouth spray doesn't reduce severe cancer pain in people already on opioids. That said, the studies have limitations, like missing details about all the treatments people were getting.

Confidence is low in the results on synthetic cannabinoids for chemo-related pain and on how they compare with morphine-type drugs, because there's so little data and the studies were small.

Likewise, confidence is low in the evidence on how well CBD works in palliative care, simply because there are so few studies in this area.