Note: This is Part 1 of a series of articles on medicinal cannabis and cancer. We will link to the other articles in the series as they are published.
Cancer touches the lives of all of us. If you haven’t experienced the disease personally, chances are you know a relative or friend who has.
Cancer is the single biggest killer in New Zealand, accounting for nearly a third of all recorded deaths.
More than 20,000 people are diagnosed with cancer in New Zealand (around 18 million worldwide) each year.
By 2040, the number of diagnoses is predicted to more than double to around 52,000 a year, or 142 people a day.
A cancer diagnosis is devastating news for anyone to get and is often accompanied by waves of fear, anger, grief, and uncertainty.
And while it’s estimated that about one person in every three who gets cancer is cured, the journey back to full health can be long and challenging.
The prevalence and high mortality rate of cancer means that patients, doctors and researchers are always looking for medical breakthroughs.
There are many effective treatments available, including surgery, chemotherapy, radiation therapy, and immunotherapy.
But these treatments are not always successful and can come with unpleasant side effects.
In more recent years, scientists have been researching the potential of medicinal cannabis in cancer treatment.
Studies have found that cannabis may help to alleviate common cancer symptoms and treatment side effects, such as pain, nausea, loss of appetite and anxiety.
Cannabis has also been found to have anti-tumor effects, which may help to slow or stop the growth of cancer cells in the body.
There is no evidence that cannabis is a “cure” for cancer and any such claims should be disregarded.
However, if you’ve been diagnosed with cancer or you know someone who has, you may be interested in learning how medical cannabis can help to provide relief.
What this article covers
This article covers the potential of cannabis to help alleviate common cancer symptoms and the side effects of cancer treatments.
Part 2 will look at the research into the anti-cancer (or anti-tumor) potential of medicinal cannabis.
What is cancer? An overview
Cancer is the name given to a collection of related diseases in which cells begin to grow out of control.
There are more than 100 types of cancer, which are typically named after where the disease is located in the body.
Our bodies are made up of more than 100 million cells that are carefully regulated by our genes.
Cancer starts when a healthy cell (or group of cells) is damaged, which is also known as a “gene mutation”.
Usually, a damaged cell will die. But cancer cells continue to divide, grow and spread uncontrollably.
As cancer cells spread throughout the body they can interfere with our vital organs and affect functions required to keep us alive and well.
The rapid growth and division of cancer cells often creates tumors, which are abnormal masses of tissue (or lumps of cells that don’t die when they should).
Because there are so many different types of cancer that affect different parts of the body, the symptoms can vary widely.
However, some of the most common symptoms of cancer are:
- Weight loss or gain
- Appetite loss
- Nausea and vomiting
- Sleep disorders
- Anxiety and depression
Common cancer treatments
Cancer treatments use drugs or therapies to kill the cancer cells or to stop them from growing or spreading throughout the body. Patients can also have surgery to remove tumors.
The most common treatments today are:
- Chemotherapy: Chemotherapy is a treatment that uses one or more anti-cancer drugs given as an infusion into a vein. The drugs are designed to stop or slow the growth of rapidly dividing cancer cells. Some chemotherapy drugs can be taken in pill or capsule form. Patients typically require multiple cycles of chemotherapy.
- Radiation therapy: Radiation therapy is a treatment that uses high doses of radiation to kill cancer cells and shrink tumors. A typical course of radiation therapy is given daily (five days a week, excluding weekends, to allow the healthy cells to recover) for three to six weeks.
- Surgery: Surgery can be performed to remove cancerous tumors and surrounding tissue. This is most effective for treating localised cancer that hasn’t spread throughout the body. It can also help to improve the success of other treatments.
- Immunotherapy: Immunotherapy is a type of treatment that supports your immune system to fight cancer. It’s most commonly used with people who have advanced cancer.
Side effects of cancer treatment
Patients can often experience unpleasant side effects or symptoms of cancer treatments and therapies.
While these treatments are designed to kill cancer cells, they can also damage health cells throughout the body.
Damage to healthy cells can cause a range of side effects, including:
- Fatigue (extreme tiredness)
- Nausea and vomiting
- Loss of appetite
- Neuropathy (tingling or numbness)
- Hair loss
- Skin irritation
In some cases, the side effects of cancer treatment can be worse than the symptoms of the disease in its early stages.
However, there are ways to alleviate both the symptoms of cancer and treatment side effects.
Cannabis and cancer: Treating symptoms and side effects
Research has found that medicinal cannabis may help some patients to manage common cancer symptoms and treatment side effects.
“In cancer patients, cannabinoids have primarily been used as a part of palliative care to alleviate pain, relieve nausea and stimulate appetite.” – 2019 review
If you are not familiar with medicinal cannabis and its therapeutic compounds, it might help to familiarise yourself with some of the terms below.
- Cannabis: This refers to the whole cannabis plant, including its dried and processed forms.
- Cannabinoids: These are naturally occurring compounds in the cannabis plant.
- THC: THC is one of the main cannabinoids in cannabis. It produces the “high” feeling the plant is known for, but also has a host of therapeutic benefits.
- CBD: CBD is the other most well-known cannabinoids in cannabis. It doesn’t produce the “high” feeling.
- Nabiximols: This is a cannabis extract commonly used in clinical trials comprising roughly one part THC and one part CBD.
- Nabilone: A synthetic cannabinoid that mimics THC.
- Dronabinol: A synthetic version of THC.
- Levonantradol: A synthetic version of THC.
Cannabis and pain
Almost half of all patients with cancer experience moderate to severe pain, which has a negative impact on their quality of life.
There is some evidence to suggest that cannabis can help to alleviate cancer-related pain, whether it be a direct symptom of the disease or a treatment side-effect.
The first study looking at cannabis and pain in cancer patients was done in 1975. It found that increased pain relief correlated with higher doses of THC oil.
Various clinical studies have been done since then using nabiximols (THC and CBD blend) as treatment.
A 2012 study of 263 cancer patients found that low-to-medium dose nabiximols were “significantly more effective” than placebo for reducing average daily pain.
Medicinal cannabis has been found to provide cancer patients with some pain relief (usually a 15-30% improvement) even in cases when opioids are ineffective.
However, a 2020 review of the evidence highlighted limitations in these studies:
“Although preclinical studies have suggested promising benefits of cannabis and cannabinoids in the treatment of cancer pain, there has been a paucity of translatable evidence recommending regular use.”
The largest study looking at cannabis and pain relief in cancer patients was done in Israel in 2018.
Close to 3000 cancer patients were administered 16 different strains of THC and CBD concentrations.
After six months of follow-up, 95.9% of the remaining patients reported an improvement in their condition, including factors such as sleep problems, pain, weakness, loss of appetite and nausea.
The study concluded that cannabis as a palliative treatment for cancer patients seems to be a “well tolerated, effective and safe option to help patients cope” with their symptoms.
However, not all research has been so positive.
A 2019 review of previous studies concluded that cannabinoids “cannot be recommended for the treatment of cancer-related pain”.
The report said there was no “net overall benefit” of using cannabinoids to treat cancer-related pain and there were “significant adverse effects” to consider.
Adverse effects of cannabis observed during these studies include dizziness, nausea, vomiting, dry mouth, drowsiness, and confusion.
Cannabis and nausea/vomiting
Patients with particular types of cancer and up to 75% of chemotherapy patients can experience nausea and vomiting.
While there are effective drugs available for alleviating these symptoms and side effects, medicinal cannabis may be a better or alternative option for some patients.
“The best-established use of cannabinoids in cancer is the inhibition of chemotherapy-induced nausea and vomiting.” – Ora Pharm Medical and Research Officer, Dr Roger Negrete
In the United States, synthetic cannabinoids dronabinol and nabilone have been approved for treating chemotherapy‐induced nausea and vomiting.
A 2001 review of evidence from 30 randomised trials found cannabinoids (oral nabilone, oral dronabinol, and intramuscular levonantradol) to be “slightly better” than conventional drugs for treating chemotherapy induced vomiting and nausea.
Perhaps the most meaningful finding was that patients preferred cannabinoids over conventional drugs.
“In trials where people received cannabis-based medicines and conventional medicines in turn, overall people preferred the cannabis-based medicines.”
However, cannabinoids produced adverse effects in some patients, including dizziness, hallucinations, paranoia and depression.
Preclinical research has found that CBD may also be effective at relieving nausea and vomiting produced by chemotherapy.
Further research on the potential of cannabis for treating nausea and vomiting is underway.
Cannabis and appetite/weight loss
Cancer patients can experience unexplained weight loss (cachexia) and appetite loss (anorexia). This can be caused by the disease, treatment, or other symptoms such as nausea, pain or fatigue.
It not only reduces patients’ quality of life, it also affects the efficacy of treatment and reduces their ability to stay healthy and fight the disease.
Recreational cannabis users have long known that cannabis can cause a sudden and dramatic increase in appetite, commonly known as “the munchies”.
Research is finding that medicinal cannabis may also help increase appetite in cancer patients, which can help to reduce weight loss.
One of the most widely-reported studies, published in 2011, found that THC helped to improve appetite, taste and smell perception, caloric intake, and quality of life for cancer patients with chemosensory alterations (loss of taste and smell).
A majority of the patients who took THC reported improved appetite (64%) and a renewed ability to taste and smell food (73%).
Patients treated with THC also consumed more calories and showed a preference for high-protein foods compared with the placebo group.
However, a high-level study published in 2006 found that while cannabis extract (THC and CBD) and THC increased appetite in cancer patients, they were no more effective than the placebo.
Despite an abundance of anecdotal evidence that cannabis stimulates appetite in healthy people, there is a lack of meaningful scientific data specific to cancer patients.
More large clinical trials are needed to draw definitive conclusions.
How to get medicinal cannabis for cancer treatment in New Zealand
Medicinal cannabis is legal in New Zealand, although there are some barriers to access.
You can ask your doctor or oncologist about getting a prescription for medicinal cannabis in New Zealand.
Doctors can prescribe both CBD- and THC-based medicines for cancer-related symptoms and treatment side effects, as long as it’s “within their scope of practice”.
Medicinal cannabis won’t be suitable for everyone, but if you think it may help to improve your quality of life, you are well within your rights to talk to your doctor about getting a prescription or medical certificate.
A part of the solution
There is evidence to suggest that medicinal cannabis can help some cancer patients to better manage their symptoms and treatment side effects.
However, based on the current research, medical cannabis is not a silver bullet or cancer miracle drug by any stretch of the imagination.
Studies have found that cannabis can form part of a holistic healthcare approach for some cancer patients, particularly when it comes to managing pain, nausea and vomiting, and stimulating appetite.
There are many potential adverse side effects that come with cannabis use that patients, caregivers and doctors should be aware of.
However, with the right advice, dosage, and approach, medicinal cannabis may help some cancer patients to improve their quality of life.