There are few diseases that scare modern man as much as cancer, says oncologist Siddhartha Mukherjee in the The Emperor of All Maladies: A Biography of Cancer. In the fight against cancer, scientists around the world spend billions of dollars each year on research to combat the disease, but cancer deaths continue to rise without significant advances in cancer treatment.
If you look online for information on hemp, industrial hemp or CBD, you will come up with a plethora of articles all suggesting that hemp-derived cannabinoids (such as CBD) have anti-cancer and tumour-inhibiting properties.
But how do these studies go from laboratory research to having an effect in humans?
A review conducted by a group of researchers in Bulgaria in October 2020 summarised the anti-cancer effects of hannia-derived CBD and initially mapped out guidelines for how hannia-derived CBD could enhance or support conventional cancer treatments. Their study delves into the effects of CBD on different cancer cells and explains how, when combined with conventional anti-cancer drugs, CBD works synergistically to provide improved outcomes in the human body.
How does CBD target cancer?
Endogenous cannabinoids produced in the human body, as well as cannabinoids extracted from the hemp (industrial hemp) plant, play a role in regulating the changes that affect cancer, including how cancer cells grow, migrate and spread.
The cannabinoid CBD (cannabidiol) extracted from hemp is non-toxic and a well-tolerated compound with a good safety profile. A number of studies have now demonstrated that hemp-derived CBD can reduce tumour growth and progression in a variety of cancers such as breast, lung and colon cancers.
"Numerous animal and cellular experiments have shown that multiple cannabinoids, including CBD, have a variety of direct anticancer effects," said Dr. Dustin Sulak, an integrative physician and expert in cannabis medicine. He says, "In particular, CBD rarely causes adverse effects and can provide substantial relief on its own."
Researchers have now begun to look more closely at how CBD works in tandem with common chemotherapy drugs and how this potent cannabinoid can be transferred from the laboratory to the treatment room.
The effect of CBD on different types of cancer
In the above-mentioned 2020 review study from Bulgaria, the research team published evidence supporting the use of CBD for various types of cancer. The following are their findings for the three most common diseases.
CBD has an inhibitory effect on breast tumour cells, particularly on the MCF-7 cell line, which is often used in research for cancer treatment drugs. The researchers found that CBD played a more powerful role in stopping the spread of breast cancer cells compared to other cannabinoids.
In a 2012 study, CBD was found to have a mechanism to stop the spread of lung cancer tumours. The team also reported that CBD promotes cancer cell death in primary lung tumour cells.
In vitro experiments performed on different prostate cell lines showed that CBD reduced the expression of androgen receptors, which strongly influenced the development and progression of prostate cancer. Inhibition of the activity of these receptors may delay the progression of prostate cancer.
CBD inhibits tumour growth and spread
One of the most problematic features of cancer is the spread of cancerous tumours throughout the body. Unlike normal healthy cells, cancer cells express many mutations that prevent cell death. These mutated cells can then spread throughout the body and settle in multiple other locations.
Cancer research usually focuses on the primary site of cancer origin rather than the secondary site to which the cancer has spread. Notably, studies of cannabinoids such as CBD have typically focused on their ability to inhibit the progression of cancer cells that have migrated and begun to form new tumours.
According to a review of Bulgarian studies, CBD promotes tumour suppression through multiple pathways in vivo. one of the most important ways in which CBD may slow tumour progression is through its regulation of PI3K, the main pathway regulating cell growth, metabolism, survival and proliferation, and therefore represents a target for cancer therapy.
How CBD can be combined with cancer therapy
According to the Bulgarian review, many reports advocate the use of combination therapy. Combining CBD with specific anti-cancer drugs has been shown to make certain cancer cells more susceptible to the effects of cancer drugs.
Other landmark studies in pancreatic cancer patients have shown that CBD combined with chemotherapy can produce positive results, a type of cancer known for its treatment resistance. When conventional cancer treatments were combined with CBD, mice with pancreatic cancer lived nearly three times longer. In addition to extending life, CBD can also improve sleep quality and reduce pain.
Another study has shown that CBD and conventional treatment with temozolomide can be more successfully combined to treat gliomas (tumours of the brain and spinal cord).
Side effects of CBD for cancer treatment
There is also a large body of research supporting the use of CBD as an adjunctive medicine to prevent and reduce the side effects of cancer therapy. One of the most undesirable side effects of potent anti-cancer drugs is neuropathy, which causes weakness, numbness and pain in the hands and feet. Some chemotherapies can cause this condition to be experienced by up to 75% of patients.
CBD can help prevent the development of this sensitivity. According to a 2014 study on mice, CBD reduces the neurological effects of paclitaxel (a form of chemotherapy) and may prevent the development of neurosensitivity in mice. Importantly, the nervous system of the mice was not harmed and the efficacy of the chemotherapy was not affected by the treatment.
Another study showed that CBD supported the kidneys and reduced the nephrotoxicity induced by cisplatin, a chemotherapeutic agent associated with kidney damage.
Will the future of cancer treatment be heavily weighted towards the use of CBD?
Like many nascent areas of hemp science, there is currently very limited data exploring CBD and cancer therapies. However, the 2020 Bulgarian review is packed with evidence that suggests that hannum-derived CBD can complement many forms of cancer treatment, but also that more and more comprehensive clinical studies are needed to test its effectiveness.
This review succinctly summarises data on the ability of CBD to inhibit a wide range of cancers and to act synergistically with conventional anti-cancer drugs. While we have much to learn about how CBD maximises its potential benefits in humans, the safety, tolerability and symptom improvement of CBD provide strong evidence for the use of hemp-derived CBD in cancer patients.