According to cell and animal models, CBD helps promote cancer cell death. Will it work in humans?
Researchers have found that cannabis provides pain relief in patients with advanced cancer. Findings also reveal that some cannabis treatments have better anti-nauseant efficacy compared to traditional anti-emetic drugs taken during chemotherapy. However, emerging research suggests that cannabis may not only be efficacious as a treatment for the symptoms of cancer and cancer treatment, but as a potential future direct treatment for cancer itself. Most recently, researchers are lauding the benefits that a cannabis-based treatment may have on stage 4 stomach cancer.
Scientific Basis for Cannabis-Based Cancer Treatment
The biological role of the endocannabinoid system in cancer formation is still somewhat a mystery. Although multiple studies suggest that overexpression of the endocannabinoid system has links with tumor growth. Researchers have found upregulated CB1 and CB2 receptors in breast, prostate, and melanoma cancers, indicating that the endocannabinoid system in these disorders may be out of balance. Exogenous cannabinoids (THC and CBD) target a wide range of physiological processes and pathways in the endocannabinoid system that are critical to cancer pathophysiology. However, it appears that these cannabinoid-controlled interruptions in cancer development are not always dependent on CB receptors. These interruptions are also manipulated through other receptors, such as TRPV1 and 5-HT.
The mechanism of action for cannabis to mediate cancer cell growth and death may be complex. However, several pre-clinical studies demonstrate that cannabis can control cancer cell proliferation and promote cancer cell death. It’s important to recognize that pre-clinical means that while research has advanced to the animal-testing phase, it has not yet been trialed on humans.
CBD Promotes Cell Death in Stage 4 Stomach Cancer
In a study published in Cell Death and Disease (2019), the researchers assessed the effectiveness of CBD on various types of stomach cancer cells outside (in vitro) and inside (in vivo) living organisms. In vitro CBD treatment to stomach cancer cells demonstrated decreased cell proliferation without any effect in healthy cells, and increased cell death in some, but not all, the stomach cancers assessed.
The in vivo CBD administration occurred in mice. The researchers injected mice with stomach cancer cells and waited until tumors reached 100 mm in size before administering CBD to a treatment group. CBD treatment occurred three times over one week, and researchers monitored tumor growth for a total of fifteen days. The results showed that the treatment group experienced significantly less tumor growth than the control group. This was despite minimal differences in body weight between the two groups. This study adds to the wealth of literature on the positive impacts cannabis can have on numerous types of cancer cells.
Cannabis-Based Treatment for Other Stage 4 Cancer
In a study published in Pharmacology & Pharmacy (2014), researchers investigated the anti-tumor and anti-inflammatory effects of CBD in human prostate cancer cells. The results indicated that CBD is a powerful inhibitor of cancer cell growth.
In a study published in Cancer Research (2006), researchers assessed the anti-cancer potential of THC in human breast cancer cells. Through activation of the CB2 receptor, THC reduced cancer cell proliferation. The cannabinoid was able to halt the progression of the cell cycle, and induce cell death. Importantly, there was no significant CB2 expression detected in healthy breast tissue.
In a study published in Cannabis and Cannabinoid Research (2018), scientists identified several synthetic cannabinoid compounds that reduced colorectal cancer cell lines. Interestingly, natural cannabinoids, THC and CBD, either had no effect on these cancer cells, or these compounds were far less potent than the synthetic compounds. These pre-clinical results are very promising, but these experiments consisted of test tubes and animal models. The interaction of cannabis and cancer cells within the human body may be drastically different. Human trials must happen soon in order to move cancer-related cannabis research forward.
Human Trials in Cannabis in Stage 4 Stomach Cancer
Some cancers, such as breast, are sometimes heavily resistant to conventional therapies. Pre-clinical evidence suggests that cannabis may be a viable co-therapy. However, clinical trials investigating the real-world potential of cannabis as a cancer treatment are extremely limited. In one small study, published in the British Journal of Cancer (2006), consisting of nine participants with recurrent glioblastoma multiforme, the researchers injected participants with THC intratumorally. Unfortunately, only two participants had any measurable positive effects. This result occurred despite THC’s inhibition of tumor growth in vitro.
Additionally, there was no significant clinical benefit. It is also important to note that the patients in this study had previously failed conventional therapies like surgery and radiotherapy, a key ethical consideration for cannabis-related cancer research.
Ethical Considerations for Future Cannabis Cancer Research
Is it ethical to provide a cancer patient with a new experimental therapy when an already established treatment exists? Many would say that it is not. This ethical concern could be problematic for future cannabis research. The previously mentioned human trial had participants who had already failed other proven treatments. This meant that providing them with cannabis was ethical because all other options had been explored. However, these groups of cancer patients may not always be available for research. Additionally, if a patient is already past help from standard treatments, cannabis treatment may also be ineffective anyway.
Despite these challenges, there is a reason to be hopeful. The medical community should not ignore the established pre-clinical evidence supporting cannabis as a potential therapeutic agent in various cancers. Instead, it should inform ethically conducted human trials to better understand the power of cannabis for cancer treatment.