Cannabis, CBD oil and cancer
Cannabis is a plant and a class B drug. It affects people differently. It can make you feel relaxed and chilled but it can also make you feel sick, affect your memory and make you feel lethargic. CBD oil is a chemical found in cannabis.
- Cannabis has been used for centuries recreationally and as a medicine.
- It is illegal to possess or supply cannabis as it is a class B drug.
- Research is looking at the substances in cannabis to see if it might help treat cancer.
- There are anti sickness medicines that contain man-made substances of cannabis.
What are cannabis and cannabinoids?
Cannabis is a plant. It is known by many names including marijuana, weed, hemp, grass, pot, dope, ganja and hash.
The plant produces a resin that contains a number of substances or chemicals. These are called cannabinoids. Cannabinoids can have medicinal effects on the body.
The main cannabinoids are:
- Delta-9-tetrahydrocannabinol (THC)
- Cannabidiol (CBD)
THC is a psychoactive substance that can create a ‘high’ feeling. It can affect how your brain works, changing your mood and how you feel.
CBD is a cannabinoid that may relieve pain, lower inflammation and decrease anxiety without the psychoactive ‘high’ effect of THC.
Different types of cannabis have differing amounts of these and other chemicals in them. This means they can have different effects on the body.
Cannabis is a class B drug in the UK. This means that it is illegal to have it, sell it or buy it.
CBD oil, cannabis oil and hemp oil
There are different types of oil made from parts of the cannabis plant. Some are sold legally in health food stores as a food supplement. Other types of oil are illegal.
CBD oil comes from the flowers of the cannabis plant and does not contain the psychoactive substance THC. It can be sold in the UK as a food supplement but not as a medicine. There is no evidence to support its use as a medicine.
Cannabis oil comes from the flowers, leaves and stalks of the cannabis plant. Cannabis oil often contains high levels of the psychoactive ingredient THC. Cannabis oil is illegal in the UK.
Hemp oil comes from the seeds of a type of cannabis plant that doesn’t contain the main psychoactive ingredient THC. Hemp seed oil is used for various purposes including as a protein supplement for food, a wood varnish and an ingredient in soaps.
Why people with cancer use it
Cannabis has been used medicinally and recreationally for hundreds of years.
There has been a lot of interest into whether cannabinoids might be useful as a cancer treatment. The scientific research done so far has been laboratory research, with mixed results, so we do not know if cannabinoids can treat cancer in people.
Results have shown that different cannabinoids can:
- cause cell death
- block cell growth
- stop the development of blood vessels – needed for tumours to grow
- reduce inflammation
- reduce the ability of cancers to spread
Scientists also discovered that cannabinoids can:
- sometimes encourage cancer cells to grow
- cause damage to blood vessels
Cannabinoids have helped with sickness and pain in some people.
This means a cannabis based product used to relieve symptoms.
Some cannabis based products are available on prescription as medicinal cannabis. The following medicines are sometimes prescribed to help relieve symptoms.
Nabilone is a drug developed from cannabis. It is licensed for treating severe sickness from chemotherapy that is not controlled by other anti sickness drugs. It is a capsule that you swallow whole.
Sativex is a cannabis-based medicine. It is licensed in the UK for people with Multiple Sclerosis muscle spasticity that hasn’t improved with other treatments. Sativex is a liquid that you spray into your mouth.
Researchers are looking into Sativex as a treatment for cancer related symptoms and for certain types of cancer.
How you have it
Cannabis products can be smoked, vaporized, ingested (eating or drinking), absorbed through the skin (in a patch) or as a cream or spray.
CBD oil comes as a liquid or in capsules.
Prescription drugs such as Nabilone can cause side effects. This can include:
- increased heart rate
- blood pressure problems
- mood changes
- memory problems
Cannabis that contains high levels of THC can cause panic attacks, hallucinations and paranoia.
There are also many cannabis based products available online without a prescription. The quality of these products can vary. It is impossible to know what substances they might contain. They could potentially be harmful to your health and may be illegal.
Research into cannabinoids and cancer
We need more research to know if cannabis or the chemicals in it can treat cancer.
Clinical trials need to be done in large numbers where some patients have the drug and some don’t. Then you can compare how well the treatment works.
Many of the studies done so far have been small and in the laboratory. There have been a few studies involving people with cancer.
Sativex and temozolomide for a brain tumour (glioblastoma) that has come back
In 2021, scientists reported the final results of a phase 1 study to treat people with recurrent glioblastoma (a type of brain tumour that has come back). The study looked at Sativex in combination with the chemotherapy drug temozolomide.
Researchers found that adding Sativex caused side effects, which included, vomiting, dizziness, fatigue, nausea and headache but patients found the side effects manageable.
They also observed that 83 out of 100 people (83%) were alive after one year using Sativex, compared to 44 out of 100 people (44%) taking the placebo.
However, this phase 1 study only involved 27 patients, which was too small to learn about any potential benefits of Sativex. The study wanted to find out if Sativex and temozolomide was safe to take by patients.
Researchers have now started a larger phase 2 trial called ARISTOCRAT, to find out if this treatment is effective and who might benefit from it. Speak to your specialist if you want to take part in a clinical trial.
Sativex and cancer pain
There are trials looking at whether Sativex can help with cancer pain that has not responded to other painkillers.
The results of one trial showed that Sativex did not improve pain levels. You can read the results of the trial on our clinical trials website.
Cancer and nausea and vomiting
A cannabis based medicine, Nabilone, is a treatment for nausea and vomiting.
A Cochrane review in 2015 looked at all the research available looking into cannabis based medicine as a treatment for nausea and sickness in people having chemotherapy for cancer. It reported that many of the studies were too small or not well run to be able to say how well these medicines work. They say that they may be useful if all other medicines are not working.
A drug called dexanabinol which is a man made form of a chemical similar to that found in cannabis has been trialled in a phase 1 trial. This is an early trial that tries to work out whether or not the drug works in humans, what the correct dose is and what the side effects might be. The results are not available yet. You can read about the trial on our clinical trials database.
Word of caution
Cannabis is a class B drug and illegal in the UK.
There are internet scams where people offer to sell cannabis preparations to people with cancer. There is no knowing what the ingredients are in these products and they could harm your health.
Some of these scammers trick cancer patients into buying ‘cannabis oil’ which they then never receive.
You could talk with your cancer specialist about the possibility of joining a clinical trial. Trials can give access to new drugs in a safe and monitored environment.
The science blog on our website has more information about cannabis and cancer.
CBD in Treating Cancer and Related Symptoms
An Emerging and Alternative Therapy That Still Requires Much Investigation
Verywell Health articles are reviewed by board-certified physicians and healthcare professionals. These medical reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more.
Gagandeep Brar, MD, is a board-certified hematologist and medical oncologist in Los Angeles, California.
Cannabidiol (CBD) is one of many compounds (called cannabinoids) found in the marijuana plant Cannabis sativa. CBD is known for its relaxing and pain-soothing effects.
CBD is non-psychoactive, so it does not give you the classic mind-altering euphoria or “high” felt from using marijuana—that effect comes from the cannabinoid called THC (tetrahydrocannabinol).
While the research is still very early, experts speculate that CBD may play a role in treating cancer, specifically by slowing tumor growth and inducing the death of cancer cells. CBD may also help manage unpleasant symptoms related to cancer and chemotherapy, such as pain, nausea, and vomiting.
CBD and Treating Cancer
There are a number of studies supporting CBD’s potential anti-cancer role—however, the majority are limited to in vitro and animal studies. For example, in various studies, there is evidence that CBD decreases the growth of lung and prostate tumors, provokes the cell death of colon, lung, and brain cancer cells, and reduces the spread (metastasis) of breast cancer.
While promising, large human clinical trials are needed to better understand whether CBD is truly effective in helping to treat cancer. Clinical trials would also allow experts to tease out issues like dosage, interaction with other cancer drugs, and CBD’s safety profile.
As of now, there are only a handful of human studies that have examined CBD’s anti-cancer role.
Here are a few examples:
- In one study of 119 cancer patients (most of the cancers were metastatic and traditional cancer therapies had been exhausted), CBD oil was given on a three day on and three days off schedule. In most of the patients, an improvement in their cancer was noted, such as a decrease in tumor size. No side effects from CBD were reported.
- In a case study, an elderly man with lung cancer refused traditional chemotherapy and radiation for his cancer treatment and instead, self-administered CBD oil. After one month of taking the CBD oil, a computed tomography (CT) scan revealed near-total resolution of his lung tumor along with a reduction in the number and size of chest lymph nodes.
- In another study, two patients with aggressive gliomas (a type of brain tumor) were given CBD capsules in addition to chemoradiation and a multidrug regimen. Both patients had a positive response to the treatment with no evidence of disease worsening for at least two years.
Keep in mind—these studies are extremely small and lack a control group, so no finite conclusions can be drawn from them. Nevertheless, they spark further interest in the possible role of CBD in treating cancer.
CBD and Treating Cancer-Related Symptoms
There is scientific evidence, although limited and not robust, that CBD, THC, or a combination of the two, may be effective in alleviating certain cancer-related symptoms, such as pain, appetite loss, and chemotherapy-induced nausea and vomiting.
For instance, the drugs Marinol (dronabinol) and Cesamet (nabilone), which are synthetic forms of THC, are approved in the United States for treating chemotherapy-induced nausea and vomiting. Research suggests that dronabinol may also improve the taste of food, appetite, sleep, and quality of life in cancer patients.
In addition, a mouth spray that contains both THC and CBD (called Sativex) is being investigated for its role in treating cancer pain (especially nerve-related pain) that is poorly controlled by opioids. The drug is currently not available in the United States, but it is available in Canada for treating advanced cancer pain.
Lastly, research has found that in the general population (so not necessarily patients with cancer), CBD can reduce anxiety and improve sleep quality. This finding is helpful, considering the diagnosis and treatment of cancer is often overwhelming and wrought with fear and worry.
With the potentially emerging use of CBD in treating cancer and/or its related symptoms, there are a few issues to consider.
CBD oil is perhaps the most commonly utilized formulation of CBD, as it’s easy to use and allows for a high dose of consumption. However, CBD comes in many other forms—gummies, tinctures, capsules, vapes, and ointments, to name a few.
Sorting out how to best administer CBD to patients with cancer may prove to be challenging, as various formulations may work or absorb differently.
While research suggests that CBD is generally well-tolerated, we need to more closely examine potential side effects in patients with cancer. In addition, we still do not know the long-term effects of taking CBD, or how it interacts with other medications.
Short-term side effects of CBD may include:
- Reduced or increased appetite
- Weight gain or loss
- Increase in liver enzymes
If CBD is combined with THC (in the form of medical marijuana), other side effects may occur, such as:
- Dry mouth
- Disorientation and confusion
- Loss of balance
While CBD by itself is federally legal (as long as the product is derived from hemp and contains no more than 0.3% THC), marijuana is not (although, it is legal in some states).
CBD is only available by prescription in the United States in the form of a drug called Epidiolex. This drug is used to treat refractory epilepsy.
Due to these legal conundrums, CBD products may not be as tightly regulated as hoped. With that, products that claim they have a certain CBD dosage may actually contain a different amount or even contain traces of THC. This is why it is important to only take CBD under the guidance of your personal healthcare provider.
A Word From Verywell
The prospect of incorporating CBD into cancer care is intriguing but still requires much more investigation. Until then, if you are considering trying CBD (whether you have cancer or not), it’s best to talk out the pros and cons with your healthcare provider.