Decoding Cannabis: can medical cannabis improve quality of life during cancer treatment?

Cancer treatment saves lives, no two ways about it. But it also takes a toll. 

The pain, the sickness, the sleep that refuses to come, the quiet panic that can build with each appointment. These are not rare side effects. They are part of the cancer treatment experience for many.

For some, the treatment itself (and the side effects cancer treatment causes) can be just as difficult to deal with as the disease itself. 

The medications used, including chemotherapy, anti-nausea tablets, opioid painkillers, steroids, and sleeping aids, often come with costs of their own - constipation, brain fog, emotional flatness, heavy anxiety, and sometimes dependence. When those medicines fall short or the side effects become extremely disruptive (as they sometimes do), patients quite understandably look elsewhere for the help they need. 

Quality of life can take a backseat when the goal is survival. But for many, that trade-off becomes harder to accept as treatment goes on. 

Enter medical cannabis. 

With the global shift that has been underway over the past decade or so, and the ‘developed’ world beginning to loosen its grip on cannabis prohibition, more patients are gaining access to legal cannabis as a supportive treatment during cancer care. 

Not as a cure, but for greater relief. 

Relief for something that might help with the nausea and vomiting, the pain, the anxiety, depression, and the exhaustion - all brought on by the cancer itself or as a side effect of the conventional treatment options. For something that might make the days more bearable.

Welcome back to Decoding Cannabis

Decoding Cannabis is our new blog series where we take one recent piece of medical cannabis research and break it down. Not to lessen the impact or the worthiness of the research, but to make it more accessible to those not working in medicine or academia. 

Good research is only useful if everyone can understand it, especially the people affected by the data or health issue being researched. 

Today, we are going to dissect an expert summary from 2021 titled “The Management of Cancer Symptoms and Treatment-Induced Side Effects With Cannabis or Cannabinoids”. It brings together clinical insights, current evidence, and the research gaps that were identified from a National Cancer Institute symposium, with a clear focus on how cannabis is being used to manage the side effects of cancer treatment.

Cannabis is being administered to manage a range of cancer-related symptoms/side effects

The study opens with a simple fact: people with cancer are already using cannabis. Usually without formal guidance, and often to manage more than one symptom at once.

Pain, nausea, appetite loss, poor sleep, mental health concerns, and trauma are all common and all distressing. For many, medical cannabis offers a way to address several of these at the same time in what is called a multifaceted approach. It is not about finding a cure. It is about feeling better during treatment or in recovery.

When this paper was published in 2021, clinical support for medical cannabis applications in cancer care was still limited in many parts of the world. Thankfully, that has changed rapidly in the UK. At Releaf, our world-class clinical team includes specialist doctors and clinicians with real-world experience helping cancer patients with medical cannabis. 

The questions raised in this study (about when cannabis helps, how it’s best used, and who can oversee it) are ones we engage with every day in practice.

The study highlighted THC’s potential to ease that burden 

In animal models, it was shown THC reduced multiple kinds of pain and amplified the effect of opioid, meaning lower doses were needed. That’s the “opioid-sparing” effect researchers hoped to confirm in humans.

But, clinical trials have been mixed. Some patients using Nabiximols (a 1:1 blend of THC and CBD) saw modest improvements in pain scores and sleep. While THC administration did reduce some patients' need for opioids, opioid use didn’t always go down, and the pain relief wasn’t always consistent at higher doses.

That’s the catch: too much THC can backfire. Among the findings, researchers stressed the need for slow, patient-guided dosing, ideally supported by specialist clinical oversight, with titration as the central approach - exactly what is offered to all Releaf patients. 

Cannabinoids may help reduce nausea and vomiting from chemotherapy

Chemotherapy-induced nausea and vomiting (CINV) is one of the most difficult side effects to manage, especially when standard anti-nausea pharmaceuticals fall short. In the US and UK, THC-based medicines like Dronabinol and Nabilone are already approved specifically for this purpose.

The authors drew attention to mixed results across trials. In some cases, patients noted less vomiting and felt better overall, while others didn’t see much of a difference. But in people who didn’t respond well to conventional antiemetics, cannabinoids often showed real promise.

In the UK, the NHS does technically allow access to cannabis-based medicines for CINV. But in practice, NHS prescriptions are rare, and the process is long and complex. 

Clinics like Releaf provide a much more direct path to treatment, with faster access and expert clinical oversight for those who need help now.

Are cannabinoids effective for chemotherapy-related nausea and vomiting?

According to this study, researchers have observed that many patients preferred cannabis-based treatments, even with side effects like dizziness, drowsiness or mild intoxication. That patient preference, especially in the context of treatment fatigue, can’t be overlooked.

In the UK, cannabinoids are not considered a first-line option, but when standard medications don’t do the job, they may be worth exploring - that’s how they are positioned in NHS guidance, too. Access is technically possible, but for many, the private route remains the most realistic option.

Cannabis may improve anxiety, sleep, and overall well-being 

The emotional strain of cancer is often overlooked. Anxiety, trauma, and broken sleep can wear people down long before treatment ends. 

And yet, they’re rarely treated with the same urgency as physical symptoms. 

This study found that many patients were already using cannabis to cope. Not to escape, but to feel more present, less overwhelmed. Some reported sleeping better. Others described a quiet lift in mood. In cancer trials, Nabiximols (a 1:1 THC/CBD blend) offered small but meaningful gains in sleep and satisfaction

What does the study say about cannabis and emotional well-being? 

Patients spoke of a “positive shift” in outlook. A bit more calm and a hefty reduction in overwhelming fear. That kind of change matters when each day feels uphill. 

Still, the evidence is early. Especially when it comes to anxiety in cancer care. 

THC’s effects depend heavily on dose. Low levels of THC have been shown, time and again, to help reduce anxious thoughts and feelings, but just a little too much can make anxiety worse. The study underlined that careful, personalised dosing is key. 

And that is what many Releaf patients have already experienced - check out our backlog of patient stories, where you'll find so many patients sharing their positive outcomes relating to anxiety control, pain relief, improved sleep, and much more. 

Louise’s story might be of particular interest - 

“I got a phone call from my surgeon. He said, “I’m really sorry to say this, but it looks like two nodules on your lungs have appeared.”

We cancelled the implant removal and, six weeks later, they removed the two nodules and two glands from my chest. About a month later, all looked clear, until a special blood test came up positive for tumour cells in my lungs. That's when they gave me a prognosis of six to 12 months, which was not what we were expecting. My oncologist recommended that I start level IV chemo right away, so that’s what we did….

The side effects from the chemo are horrendous. The tiredness is the worst one, but the nausea and diarrhoea are also horrific—I never know when the nausea is coming, there's no rhythm to it…

That’s why I came to Releaf in the first place… my priority is only to be comfortable… 

The first big change that I noticed was my sleep. It seemed to calm my mind and helped me sleep much better at night… 

I used to take the antianxiety tablet Lorazepam at night to sleep, and I'm not taking those any more… My medicine is prescribed for me and my particular condition, it’s not just a standard dose that’s given to everyone. It’s personal… The oil really works for my side effects”

Medical cannabis dosing and delivery method impact outcomes and safety

Researchers observed that how you take medical cannabis matters more than most people think. 

Inhaled THC is rapidly effective, but that speed comes with some small trade-offs. And when products are unregulated or poorly labelled, the risk of adverse effects goes up. So does the chance of getting the dose wrong. 

All medical cannabis products prescribed to Releaf patients are fully regulated, lab tested, and dispensed through licensed UK pharmacies. Each one is clearly labelled and traceable back to source, so patients know exactly what they’re taking and clinicians can guide them with confidence.

That level of oversight makes a big difference. It means adjustments aren’t guesswork. When something needs changing, it can be done safely, accurately - with the patient’s needs at the forefront. 

What are the pros and cons of different delivery methods?

Oral routes, like oils and capsules, offer a gentler onset and often feel more stable - but they come with unpredictability. Absorption can vary from one person to the next, and even from one day to another. The same dose might feel subtle one day, then overwhelming the next. That’s the nature of digestion and metabolism, unfortunately, they don’t always run on schedule.

Most cancer-related studies still focus on oral cannabis, while inhaled products have mainly been studied for neuropathic pain. That leaves a gap in the evidence base, especially for patients with complex symptom profiles.

At Releaf, many patients land somewhere in the middle. 

Sublingually administered medical cannabis oils (held under the tongue rather than swallowed) are faster-acting and more bioavailable than when swallowed, yet easier to dose and manage for some patients than inhaled medical cannabis. 

Can medical cannabis improve quality of life during cancer treatment?

While the researchers were cautious in their conclusions, this study is just the tip of the iceberg. 

Formal clinical evidence and anecdotal findings are mounting, but more clinical data and human trials are sorely needed. 

For patients pushing through the heavy toll that cancer treatment often brings, medical cannabis may offer relief where other options fall short, especially when care is personalised and prescribed (and then continually monitored) by a specialist clinician.

If you’re considering medical cannabis treatment, head to our fast and free medical cannabis eligibility checker to see if it's potentially right for you in less than 20 seconds.