No solid proof cannabis oil can ‘cure’ cancer

9 August 2022
What was claimed

Cannabis oil can cure cancer.

Our verdict

While there is good evidence that some cannabis products can be beneficial to cancer patients to manage pain or treatment of side effects, there is no evidence it can cure the disease.

A post on Facebook, shared hundreds of times, claims that a “60 gram supply of Cannabis Oil” is “enough to treat one cancer patient”. It also includes an image of several plastic syringes which it claims contain cannabis oil, with the caption “Cancer Cure”.

While there is evidence some cannabis products can be beneficial to cancer patients, and research on this is ongoing, there is no current proof that cannabis oil can cure cancer. 

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Claims that cannabis products can cure cancer are ‘misleading’

The Facebook post doesn’t provide any source for its claim that 60g of cannabis oil would be enough to treat one cancer patient, nor does it include any specific information about what types or stages of cancer could allegedly be treated with cannabis oil. 

Cannabis oil is extracted from the flowers, leaves and stalks of the cannabis plant and, unlike CBD (Cannabidiol) which can legally be sold as a food supplement in the UK, often contains high levels of the psychoactive ingredient Delta-9-tetrahydrocannabinol (usually known as THC). Cannabis oil is therefore illegal in the UK. 

Cancer Research UK, which describes itself as “supportive of properly conducted scientific research into cannabis and its derivatives that could benefit cancer patients”, says: “The current consensus is that, right now, there isn’t a large enough body of evidence to prove that cannabis (or any of its active compounds or derivatives) can reliably treat any form of cancer but the medical use of cannabis to treat cancer-related chronic pain is approved in the UK.” 

It also says: “Claims that there is solid ‘proof’ that cannabis or cannabinoids can cure cancer are highly misleading.”

Professor Edzard Ernst, emeritus professor at the University of Exeter, told Full Fact: “Cannabinoids have been shown to reduce the size of prostate cancers in animal models. Isolated case reports have yielded encouraging findings also in human cancers, for instance, acute lymphoblastic leukaemia. 

“However, case reports cannot be considered reliable evidence, and there is currently no data from rigorous clinical trials to suggest that cannabis products will alter the natural history of any cancer.”

The image used in the post does appear to have originally been written with a US audience in mind. The American Cancer Society states: “At this time, the US Drug Enforcement Administration (DEA) lists marijuana and its cannabinoids as Schedule I controlled substances. 

“This means that they cannot legally be prescribed, possessed, or sold under federal law. Whole or crude marijuana (including marijuana [cannabis] oil or hemp oil) is not approved by the US Food and Drug Administration (FDA) for any medical use. 

“But the use of marijuana to treat some medical conditions is legal under state laws in many states.”

The FDA has approved two cannabinoids for the treatment of nausea and vomiting caused by chemotherapy in patients who have not responded to other anti-sickness treatments, but  neither cannabis or cannabinoid products have been approved as treatment for cancer itself. 

Cannabis products can be prescribed for cancer patients and further research is underway 

While cannabis products are not a proven “cure” for cancer, the Cancer Research UK article goes on to state that there is “good evidence that cannabinoids may be beneficial in managing cancer pain and side effects from treatment”. 

Cannabinoids are the different substances or chemicals found in the resin extracted from cannabis plants. The two main cannabinoids are THC and CBD. 

Macmillan Cancer Support says research has shown that cannabinoids can cause a cell to die, stop cells from dividing and stop cells from developing blood vessels. However, research has also shown that cannabinoids can damage important blood vessels, encourage cancer cells to grow in some situations and make the immune system less effective. 

Some cannabis-based products are already available on prescription for a small number of patients suffering from specific diseases. Nabilone, a synthetic cannabinoid taken as a capsule, can be prescribed to adults who are suffering with nausea caused by chemotherapy to treat their cancer. 

Sativex, which is prescribed to some people with multiple sclerosis, is a cannabis-based medicine that is sprayed into the mouth. Researchers are looking into Sativex as a treatment for cancer-related symptoms and certain types of cancer. 

Large-scale clinical trials in the UK have found no difference in self-reported pain scores between the treatment and the placebo groups, but in 2021 researchers conducting a small study of 27 patients with a specific type of brain tumour found that more participants who took Savitex in combination with the chemotherapy drug temozolomide were alive after one year (83%) when compared to the participants who had the placebo (44%). But the small sample size means that study doesn’t prove the treatment was beneficial.

But experts have stressed that this study was too small to confirm any potential benefits of Savitex and was designed to find out if it was safe for patients to take. It was reported in 2021 that the second phase of the clinical trials would start in 2022. 

Cancer Research UK has also supported research in this field carried out by other scientists such Dr Laureano de la Vega at the University of Dundee who has explored the impact of CBD on cancer cells’ ability to spread and Professor Chris Paraskeva in Bristol who investigated the effect of cannabinoids on bowel cancer.

Image courtesy of Enecta Cannabis extracts

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