Cannabis During Cancer Treatment: Nausea, Appetite and Pain, Study by Study

Cannabinoids have their best evidence in cancer care against chemo-induced nausea and vomiting, where oral THC drugs like dronabinol and nabilone have helped patients who don't respond to standard meds. For cancer pain, the picture is much weaker: CBD drops get a lot of buzz, but the evidence is still limited and they don't replace conventional painkillers. Below, what the studies actually say about managing pain and quality of life.

From what the research shows to how these products are taken, here's the no-hype version, so you know what cannabis can and can't realistically do alongside cancer treatment.

Do CBD drops help with cancer pain in adults?

In palliative care, the big question is whether cannabis-based medicines are an effective option for cancer pain. The key takeaway from the main review on the subject: these medicines did not relieve pain in cases that hadn't responded to morphine-like drugs.

On top of that, the studies reviewed didn't give clear answers on where these medicines would fit in the World Health Organization's (WHO) pain ladder for cancer. The review stresses the need for better-designed trials to properly evaluate the role of cannabis-based medicines in cancer treatment.

Cancer pain is a reality for a lot of people, and it tends to get worse as the disease progresses. The WHO recommends morphine-like medications for moderate to severe cancer pain. Even so, somewhere between one in six and one in ten people with cancer pain don't get enough relief from them.

How are cannabis products for pain taken?

To fill that gap, several cannabis-based products have been proposed as alternatives. They include cannabis flower, inhaled or taken by mouth, as well as oils, sprays and tablets containing active cannabis compounds.

Some patients report real pain relief, but the current studies make it clear that trial design has to improve before anyone can say how well cannabis medicines work for cancer pain.

What do studies say about cannabis oil for cancer pain?

The main goal of the research was to find out whether cannabis-based medicines relieve pain in people living with cancer, and whether they come with unwanted or harmful effects.

The researchers reviewed clinical trials comparing cannabis medicines with other cancer pain treatments in adults. They analyzed and summarized the results, taking into account things like study methods and sample sizes.

They found 14 studies covering 1,823 people. The trials were run in several countries, most of them in North America. Some gave cannabis medicines for short periods, while others went on for several weeks.

Cannabis medicines for cancer pain: the main results

• A mouth spray combining plant-derived THC and CBD was no better than placebo at reducing moderate to severe cancer pain in people already on opioids. Side effects were similar in both groups.
• A synthetic cannabinoid that mimics THC didn't seem to offer meaningful relief for pain linked to chemotherapy or chemoradiation in people with head and neck cancer and certain lung cancers.
• A single dose of a synthetic THC-like cannabinoid may offer some pain relief, but it showed no significant difference compared with a similar dose of a morphine-like drug.
• CBD didn't appear to add anything for pain in people with advanced cancer in palliative care.
• Worth noting: no studies directly tested medical cannabis flower in this setting, which shows how much more research is needed.

Cannabis for the side effects of cancer treatment: nausea, appetite and pain

Cannabis and cannabinoids have also been studied as possible tools for handling the side effects of cancer and its treatment, along with the pain that comes with it. Here's what the research shows.

Does cannabis help with chemo nausea and vomiting?

• Delta-9-THC taken by mouth, in prescription drugs like dronabinol and nabilone, has shown effectiveness against chemotherapy-induced nausea and vomiting in patients who don't respond to standard treatment.
• Nabiximols, a cannabis extract given as a mouth spray, also showed benefits for chemo-related nausea and vomiting in a clinical trial.

There have been studies on inhaled cannabis for these symptoms too, but more research is needed before anyone can back up those benefits.

Does cannabis boost appetite in cancer patients?

In clinical studies, delta-9-THC (dronabinol) was no more effective than other medications at increasing appetite in people with advanced cancer.
So far, there are no published studies on how inhaled cannabis affects appetite loss in cancer patients.

Cannabis for pain: vaporized, inhaled, sublingual and oral

According to one study, vaporizing cannabis alongside opioids gave better pain relief in chronic pain patients than opioids alone.

In randomized controlled trials, inhaled cannabis has eased neuropathic (nerve) pain in cancer patients.

Some studies of cannabis extracts taken under the tongue showed pain relief in people with advanced cancer, although the review above didn't find clear benefits.
Oral delta-9-THC has relieved cancer-related pain in several clinical studies.

That said, the US FDA has not approved dronabinol or nabilone for cancer-related pain.

In one randomized controlled trial, using non-specific cannabis products made no significant difference in symptoms or side effects in patients with advanced cancer.

Despite the progress and growing interest in cannabis and cannabinoids for people with cancer, more studies are needed to fully understand how well they work and how safe they are in this context. If you're considering them, bring it up with your oncology or palliative care team first.