CBD can stimulate the body’s endocannabinoid system, a neuromodulatory system influencing various physiological processes and possibly disease progression. How might CBD be useful in treating cancer?
Calvin Chan, Ph.D.Updated on March 22, 2023
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Promising results in both petri-dish and animal studies have led to human trials being planned to investigate the use of CBD in killing cancer cells. However, no results have been reported yet.
CBD and other cannabinoids have shown to slow down and kill cancer cells in animals. But research in humans is still lacking.
Laboratory studies and controlled trials have already shown that CBD can help reduce cancer pain and chemotherapy-induced nausea and vomiting in cancer patients. However, clinical trials are just being started to study whether CBD can be used to treat cancer directly in human patients.
Cannabis contains a variety of compounds called cannabinoids that can elicit different effects on the body through the endocannabinoid system (ECS) – a neuromodulatory system that may influence the development and progression of diseases.
So far, cannabidiol (CBD) and other cannabinoids have largely only been looked at to alleviate cancer pain and to treat chemotherapy-induced nausea and vomiting. However, some cell-based and animal studies have suggested that you might be able to use CBD for cancer due to its anti-tumor effects on certain cancer types.
Cancer is an extremely complex group of over 100 different diseases, but they all involve the uncontrolled growth and division of the body’s cells.
Normal cells in the body grow and divide in a controlled manner. They follow signals produced by the body that direct when the cells should and shouldn’t divide. For instance, cells will be instructed to grow and divide when there’s a wound to repair. ¹
But cancer begins when cells break free of these normal constraints and can begin growing and dividing uncontrollably. This happens through the accumulation of certain mutations or changes to the cell’s DNA.
Some of these mutations can be inherited from parents, which is why family history can sometimes be an indicator of cancer risk. ²
American actress Angelina Jolie famously decided to undergo a double mastectomy after having lost her mother to ovarian cancer and finding out that she inherited a mutation in the BRCA1 gene – which placed her at a higher risk of developing cancer herself.
Most mutations occur after birth and are caused by carcinogens – substances that can cause DNA damage – or other environmental factors: ³ ⁴
Alcohol – Research suggests that about 3.6% of cancers have a high correlation with chronic daily alcohol consumption.
Smokingtobacco – More than 85% of all lung cancers have a high correlation with tobacco smoking. Among the 4,000 chemicals that have been identified in tobacco smoke, almost 40 of them are known to be carcinogenic.
Viruses and bacteria – Some infectious agents such as HPVs (human papillomaviruses), hepatitis B and C, and helicobacter pylori can damage cells and tissues, increasing the risk of developing certain types of cancers.
Ultraviolet Radiation – UV rays from the sun, sunlamps, and tanning booths can damage exposed skin and increase the risk of skin cancer.
Pollutants – Many air and water pollutants are carcinogenic such as arsenic in polluted groundwater and chemicals from diesel exhaust.
Aging – Most cancers occur in people over the age of 55, largely because it can take time for cells to accumulate enough mutations to become cancerous.
According to the Centers for Disease Control and Prevention, cancer is the second leading cause of death in the United States and is exceeded only by heart disease. There are an estimated 1.6 million new cases of cancer every year and nearly 600,000 cancer-related deaths.
Cancer Subtypes and Classification
Depending on the type of cell that becomes cancerous, their behavior and response to treatment can vary. Most cancers fall into three main groups:
Carcinomas – this includes approximately 90% of cancers and arise in epithelial cells that line the skin, internal organs, and blood vessels. Most lung, breast, colon, and prostate cancers are carcinomas.
Leukemias and Lymphomas – these account for approximately 8% of cancers and arise from blood cells and cells from the immune system, respectively.
Sarcomas – these are cancers that lead to tumors in connective tissues such as muscle, bone, cartilage, tendons, and ligaments.
Cancers can then be further classified based on the tissues that they originate from. For instance, ductal breast carcinomas are a type of breast cancer that originates from cells that line the milk duct in the breast.
cbdMD is by far one of the largest CBD brands currently on the market and they’ve developed a very diverse selection of CBD oils and products.
Cannabinoids, including CBD, have gained popularity in the biomedical field due to their potential anti-cancer effects and use in managing other symptoms – such as pain and nausea – in cancer patients. ⁵
Significant research has already shown that cannabinoids – particularly tetrahydrocannabinol (THC) – can be used to treat nausea caused by cancer chemotherapy. In fact, there are two FDA-approved synthetic THCs – Dronabinol and Nabilone – for use in treating chemotherapy-induced nausea and vomiting. ⁵
THC is the principal psychoactive component of cannabis and when consumed can cause the feelings of “euphoria” or “high” that is typically associated with cannabis. ⁶ ¹⁰
CBD is non-psychoactive and does not lead to those same sensations.
Cannabinoids interact with the body’s endocannabinoid system (ECS). Endocannabinoids are naturally produced chemicals in the human body that play a role in regulating various biological processes. Research is ongoing to confirm how the ECS is involved in regulating brain function, pain, immunity, and metabolism.
Cannabinoids such as THC and CBD can mimic these natural “endocannabinoids” and can bind to endocannabinoid receptors including CB1 and CB2, causing similar effects.
THC can stimulate the CB1 receptor and prevent the release of hormones that trigger nausea and vomiting after chemotherapy. ⁶ CBD is thought to elicit a similar response by preventing the breakdown of natural endocannabinoids.
A 2010 randomized, double-blind, and placebo-controlled study in animal models from Spain found that patients with chemotherapy-induced nausea and vomiting benefited from using a 1:1 THC and CBD spray – 71% reported no vomiting as compared to 22% with the placebo. ⁷
A review of 8 different preliminary efficacy analyses also found that cannabinoids reduced neuropathic and cancer pain in patients as compared to a placebo (37% reduction with cannabinoids versus 31% with a placebo). ⁸
Early studies on the drug, Nabiximol, a 1:1 THC and CBD spray also found a reduction in patient-reported cancer pain as compared to a placebo. ⁹
These studies so far suggest that THC and CBD can have anti-nausea and anti-pain effects. However, most trials have relied on using THC and CBD together, so it’s not clear yet whether CBD can elicit the same level of benefit on its own.
Can CBD help with Cancer: Anti-Cancer Effects
Apart from its use in managing cancer-related pain and nausea, CBD products (such as CBD oil) are also being investigated for possible anti-cancer effects.
Studies on cancer cells have shown that many cancer types – including breast, prostate, and pancreatic cancer cells – all have higher than average numbers of CB1 and CB2 receptors. ¹⁰
In some studies, researchers found that the elevated levels of CB receptors in certain cancer cells were correlated with more aggressive tumors. In some instances, these cells with more highly activated CB receptors were more mobile and divided faster – possibly helping them to become more invasive. ¹¹
However, in other cancer types, such as colorectal cancer, researchers have found a lower number of CB1 receptors. A study on mice with colorectal tumors showed a correlation between lower levels of CB1 receptors and faster cancer progression. ¹²
These differences suggest there’s a lot more about how the ECS influences cancer development that has not yet been unraveled. Likewise, it remains to be determined whether CBD could be influencing other biological systems in the body outside of the ECS and CB receptors and, in general, if you can use CBD for cancer.
In petri-dish studies, the addition of CBD has been shown to kill or slow down different types of cancer cells including glioblastoma, leukemia, melanoma, lung, breast, cervical, and prostate cancer cell lines. ¹³
In mice, CBD has also been shown to slow down “angiogenesis,” a process by which new blood vessels are created to supply oxygen and nutrients to cells. Tumors rely on this process to gain access to nutrients needed for growth. By blocking angiogenesis, CBD could be useful in preventing tumors from growing. ¹⁴
What Does the Research Say?
Many new follow-up studies have since been done to examine how CBD and other cannabinoids influence cancer development in animals. However, some of the results have been conflicting. ¹⁵
The first reported study of using CBD and other cannabinoids to slow tumor growth in animals was done in 1975. Lung cancer was transplanted into animals which were then given THC or CBD over 10 days.
Researchers found that THC had a dose-dependent ability to slow tumor growth while CBD had no effect.
However, in more recent studies, CBD has been shown to have anti-tumor effects in other types of cancers.
In mice transplanted with human glioma cells – a kind of brain cancer – CBD at a dose of between 15-20 mg/kg administered over 18-28 days was effective in reducing tumor size and prolonging the animals’ survival. ¹⁶
A similar anti-cancer effect was seen in mice transplanted with other cancer types as well.
In mouse models transplanted with human breast cancer, CBD administered at 10mg/kg blocked tumor growth and prevented metastasis – a process where cancer cells can move from one organ to colonize a different one. ¹⁷
In mice injected with lung cancer cells, treating them with 5mg/kg CBD prevented the cancer cells from colonizing the lungs by 84%. ¹⁸
While these early animal studies have been promising, no work has yet been completed to evaluate the use of CBD for treating cancer in human patients.
According to the U.S. National Library of Medicine, the Hadassah Medical Organization in Jerusalem, Israel, is looking to recruit 60 participants into a clinical trial to assess the use of pure CBD in treating solid tumor cancers. Recruitment has not yet begun.
Similarly, a Spanish neurological oncology research group, GEINO, is looking to test a 1:1 THC and CBD combination drug to treat glioblastoma, a type of brain tumor with a median survival time of only approximately 12 months.
THC and CBD will be used alongside the chemotherapy drug temozolomide and radiotherapy. Doctors hope to see if hemp’s properties will be complementary medications not only for preventing the growth of cancer cells but also in treating side effects of chemotherapy, such as neuropathic pain. Recruitment has not yet begun.
While initial laboratory and animal research surrounding the use of CBD and other cannabinoids in cancer treatment has been promising, there isn’t enough evidence that they can be effective for treating cancer in humans.
Even with using CBD to treat cancer-related pain, nausea, or vomiting, users should seek out the advice and support of the medical professionals treating their cancer first.
It is also important to keep in mind that while CBD is generally safe and well-tolerated, it can also cause a wide range of side effects. ¹⁹
Some of these can include: ²⁰
Low blood pressure
Changes in appetite or weight
Significant foundational research has already been done in both cell culture and animal studies indicating an anti-cancer effect for CBD. But without human trials, it’s not clear if it’s effective to use CBD for cancer in human trials.
Nonetheless, it’s clear that the link between cancer development and the ECS makes CBD a promising avenue for cancer therapy research.
Calvin Chan is a researcher and medical writer from Edmonton, Canada. As a big science nerd, he loves reading and writing about everything science - from cannabis to dark matter and even alien life. Calvin has a PhD from the University of Alberta.