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Cannabis for cancer-related symptoms – an unfulfilled promise?

Medical cannabis is currently too far removed from the standards of medical practice, and leaving the process of selecting, dosing and taking it, almost entirely in the hands of patients, is not fair to them or their caregivers, writes Dr Marcin Chwistek, a supportive care and palliative medicine specialist, in Medpage Today.

There is a stark contrast between the excitement and promise surrounding the therapeutic use of cannabis – defined here as any product derived from the plant Cannabis sativa, such as tetrahydrocannabinol (THC) or cannabidiol (CBD) or others – and its clinical application for cancer patients seeking relief from their symptoms, he writes.

Pain, nausea, anxiety, lack of appetite, fatigue, or poor sleep plague many patients; they often overlap, and frequently persist. As a result, there is an enormous need and interest in finding new and effective ways to treat the symptoms. The available pharmaceutical therapies can help, but many have side effects and are poorly tolerated by some patients.

Many cancer patients (and their clinicians) hoped that medical cannabis would fill that gap. But the results, so far, have been (mostly) disappointing, both in the published literature and in clinical practice.

This disappointment is especially apparent for the patients with incurable cancer. A few reasons stand out. First, the current process – a result of persisting dichotomy between the state and federal laws – practically limits clinicians’ involvement in medical cannabis management to only the issuance of medical certifications. It mostly leaves the specific product, dose, and often the route of administration, up to the dispensaries and patients.

As one of my patients put it (half-jokingly): “You may have this thing around your neck,” he said, pointing to my stethoscope, “…but when I go to the dispensary, I am the doc!”

He is one of the few who have been using cannabis for decades and is familiar with its effects. But most patients with advanced cancer are not. Many are elderly and frail, take multiple medications, and receive toxic chemotherapy. They are often overwhelmed by challenges related to a life-threatening illness, and do not have the resilience and patience necessary to navigate a system that is not patient-centred.

Medical cannabis may have the “medical” in its name, but it is far removed from the standards of medical practice. A common clinical scenario is patients trying various cannabis-derived products, usually as an add-on to their established pharmacological regimens, at varying doses for multiple symptoms and usually for brief periods, with minimal supervision or medical advice.

Leaving the process of selecting, dosing and taking medical cannabis almost entirely in their hands is not fair to them or their caregivers. “I tried it once, but it didn’t work.” “I took it, felt ‘out of it’, and stopped.” “My anxiety got worse.” “It might have helped a little, but I can’t afford it.”

This is what I hear most often from patients during follow-up visits.

And yet, the underlying irony is that most patients who stopped using it could still potentially benefit from medical cannabis with proper guidance and a process that makes the application of medical cannabis more patient-centred.

The education gap is another reason the current process needs to be revised. For example, in a survey, only 30% of oncologists said they were comfortable advising patients about cannabis. Yet, two-thirds felt cannabis was helpful as an additional treatment for pain or lack of appetite.

Even the most knowledgeable pharmacists can only provide limited guidance as they cannot access the patient’s records (except the principal diagnosis) or an accurate list of medications.

Despite many published studies related to the therapeutic application of cannabis, there are only a few that can guide clinicians in practice. One recent study is an example of research examining the effects of CBD on a range of symptoms in patients with cancer receiving specialist palliative care.

CBD was chosen as it is widely available, does not have the psychomimetic effects of THC, and has shown therapeutic potential, making it an attractive agent for patients with advanced cancer. And yet, the study failed to show any significant difference between the placebo and CBD groups after 14 days.


As with any clinical trial, one needs to consider the context of the study. For example, the patients included in the study were receiving specialist palliative care (i.e. already getting pain medications, anti-anxiety medications, antidepressants, anti-nausea and other specific therapeutics).

How likely is it that adding CBD daily on top of all these other medications would be powerful enough to show the difference in two weeks?

CBD’s pharmacology is very complex. In contrast to THC, CBD does not work through the cannabinoid receptors but rather through multiple molecular targets. This probably requires time. It may also be true that CBD could be effective as an alternative to, for example, anti-anxiety medications, but this study was not set up to answer this question.

Alternatively, another explanation is that CBD’s role for patients with advanced disease and heavy symptom burden is indeed limited. Yet, based on this study, all a practising physician can gather is that adding it for a short period in a cancer patient with multiple symptoms, who is receiving palliative care, is unlikely to help. We desperately need more well-conducted research that can inform clinical practice.

I believe that medical cannabis has the potential to help many cancer patients. However, for this to happen, a lot needs to change.

We need better education for clinicians, patients and caregivers. The knowledge base related to medical cannabis is vast and growing. Cannabis can be helpful, but its use is not without risks. We need standardised products that are carefully labelled, high-quality, free of contaminants, and readily available to patients. In addition, we need robust research conducted in specific patient populations.

But mostly, we need to bring the discussions about cannabis use and benefits back to clinic rooms while forging new relationships with the industry that will allow us to think about medical cannabis in a new innovative way that is vastly different from its recreational applications.

Only then can we find ways to incorporate it into the treatment of cancer-related symptoms effectively and safely.

Dr Marcin Chwistek is a supportive care and palliative medicine specialist at Fox Chase Cancer Center in Philadelphia, USA.

Survey details

Medical Oncologists’ Beliefs, Practices, and Knowledge Regarding Marijuana Used Therapeutically: A Nationally Representative Survey Study

Ilana Braun, Alexi Wright, John Peteet, Fremonta Meyer, David Yuppa, Dragana Bolcic-Jankovic, Jessica LeBlanc, Yuchiao Chang, Liyang Yu, Manan Nayak, James Tulsky, Joji Suzuki, Lida Nabati, and Eric Campbell.

Published in Journal of Clinical Oncology on 10 May 2018


Although almost every state medical marijuana (MM) law identifies cancer as a qualifying condition, little research supports MM’s use in oncology. We hypothesised that the discrepancy between these laws and the scientific evidence base poses clinical challenges for oncologists. Oncologists’ beliefs, knowledge, and practices regarding MM were examined in this study.

In November 2016, we mailed a survey on MM to a nationally-representative, random sample of 400 medical oncologists. Main outcome measures included whether oncologists reported discussing MM with patients, recommended MM clinically in the past year, or felt sufficiently informed to make such recommendations. The survey also queried oncologists’ views on MM’s comparative effectiveness for several conditions (including its use as an adjunct to standard pain management strategies) and its risks compared with prescription opioids. Bivariate and multivariate analyses were performed using standard statistical techniques.

The overall response rate was 63%. Whereas only 30% of oncologists felt sufficiently informed to make recommendations regarding MM, 80% conducted discussions about MM with patients, and 46% recommended MM clinically. Sixty-seven percent viewed it as a helpful adjunct to standard pain management strategies, and 65% thought MM is equally or more effective than standard treatments for anorexia and cachexia.

Our findings identify a concerning discrepancy between oncologists’ self-reported knowledge base and their beliefs and practices regarding MM. Although 70% of oncologists do not feel equipped to make clinical recommendations regarding MM, the vast majority conduct discussions with patients about MM and nearly one-half do, in fact, recommend it clinically. A majority believes MM is useful for certain indications. These findings are clinically important and suggest critical gaps in research, medical education, and policy regarding MM.

Study details

Phase IIb Randomized, Placebo-Controlled, Dose-Escalating, Double-Blind Study of Cannabidiol Oil for the Relief of Symptoms in Advanced Cancer (MedCan1-CBD)

Janet Hardy, Ristan Greer, Georgie Huggett, Alison Kearney, Taylan Gurgenci, and Phillip Good.

Published in Journal of Clinical Oncology on 21 November 2022


To determine whether cannabidiol (CBD) oil can improve symptom distress in patients with advanced cancer receiving palliative care.

Participants were adults with advanced cancer and symptom distress (Edmonton Symptom Assessment Scale [ESAS] total score of ≥ 10/90) who received titrated CBD oil 100 mg/mL, 0.5 mL once daily to 2 mL three times a day, or matched placebo for 28 days. The primary outcome was ESAS total symptom distress score (TSDS) at day 14. Response was defined as a decrease in TSDS by ≥ 6 at day 14. Secondary outcomes were ESAS TSDS over time, individual symptom scores, patient-determined effective dose, opioid use, Global Impression of Change, depression, anxiety, quality of life, and adverse events.

Of the 144 patients randomly assigned, the planned sample size of 58 participants on CBD and 63 on placebo reached the primary analysis point (day 14). The unadjusted change in TSDS from baseline to day 14 was –6.2 (standard deviation, 14.5) for placebo and –3.0 (standard deviation, 15.2) for CBD with no significant difference between arms (P = .24). Similarly, there was no detected difference in proportion of responders (placebo: 37 of 63 [58.7%], CBD: 26 of 58 [44.8%], P = .13). All components of ESAS improved (fell) over time with no difference between arms. The median dose of participant-selected CBD was 400 mg per day with no correlation with opioid dose. There was no detectable effect of CBD on quality of life, depression, or anxiety. Adverse events did not differ significantly between arms apart from dyspnea that was more common with CBD. Most participants reported feeling better or much better at days 14 (53% CBD and 65% placebo) and 28 (70% CBD and 64% placebo).

CBD oil did not add value to the reduction in symptom distress provided by specialist palliative care alone.


Journal of Clinical Oncology survey article – Medical Oncologists’ Beliefs, Practices, and Knowledge Regarding Marijuana Used Therapeutically: A Nationally Representative Survey Study


Journal of Clinical Oncology article – Phase IIb Randomized, Placebo-Controlled, Dose-Escalating, Double-Blind Study of Cannabidiol Oil for the Relief of Symptoms in Advanced Cancer (MedCan1-CBD) (Open access)


Medpage Today article – The Unfulfilled Promise of Cannabis for Cancer-Related Symptoms (Open access)


See more from MedicalBrief archives:


SA’s first chronic pain clinical trial to explore cannabis as alternative to opioids


Dosing, administering medical cannabis for chronic pain – Recommendations


Doctors still reluctant to prescribe medical cannabis – Canadian study


BMJ: New clinical guidelines for medical cannabis in pain relief


Potential for cannabis to shrink cancer tumours







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