Medical Cannabis and Cancer and Chemotherapy
Medical cannabis and cannabis extracts like dronabinol, as well as the synthetic version of THC, Marinol, have long been used for managing chronic pain, nausea, insomnia, anxiety, lack of appetite, and weight loss (cachexia) associated with cancer and chemotherapy. However, there is evidence emerging about various phytocannabinoids’ anti-cancer and anti-tumoral properties.
What Is Cancer and Chemotherapy?
The classic biological definition of cancer is “unregulated cellular proliferation.” The mechanisms that allow the unregulated proliferation of cancerous cells is a realignment of cellular circuitry for growth cues. There are many different types of cancer, all of which require different treatments. Although there are different types of cancer, it can be considered a systemic disease that “Presents itself clinically by local phenomena like carcinoma, lymphoma, and sarcoma. These local manifestations may lead further to secondary systemic sequelae like metastasis.” Chemotherapy is a drug used to slow and/or kill cancerous cells in the body.
Brief Summary of Current Treatments
Many cancer treatments are usually administered at different stages of development. Surgery to remove the tumor, chemotherapy, and radiation therapy (radiotherapy) are the most well-known treatments. Others include:
- Bone marrow transplant
- Hormone Therapy
- Targeted drug therapy
- Radiofrequency ablation
Opioids are commonly prescribed for cancer pain. Although chemotherapy is often associated with cancer treatment, it is also sometimes used for multiple sclerosis (MS) treatment.
How Might Medical Cannabis Help?
Cannabis seems to work for so many cancer patients because it not only helps manage the side effects of chemotherapy (pain, nausea/vomiting, insomnia, loss of appetite) but may also help battle cancer of many types. Bladder, brain, breast, colon, endocrine, kaposi sarcoma, leukemia, lung, prostate, and skin cancers are vulnerable to medical cannabis. Medical use of cannabis is also an ideal alternative to opioids and anti-emetics, as medical cannabis has fewer adverse side effects.
The following studies also show some promise concerning treating cancer with cannabinoids:
- Cannabidiol (CBD) as a potential anti-cancer drug
- Cannabinoids – a new weapon against cancer?
- GW Pharmaceuticals Achieves Positive Results in Phase 2 Proof of Concept Study in Glioma
- Cannabinoids as therapeutic agents in cancer: current status and future implications
We also highly recommend reading the works of Dr. Cristina Sanchez. She, alongside Dr. Manuel Guzman, has looked at the possibility of using cannabis for even the most aggressive cancers, and their results are highly promising. Though much research needs to be done to discover how effective cannabis is for various kinds of cancer, there is significant anecdotal and lab data that suggests we should explore further.
To understand why cannabis may help for cancer, it is helpful to understand a little bit more about how cancers are formed and developed.
To answer this, we must look at some basic tenets of cancer biology and how cancer cells mutate to stay alive and increase as cancer cells. If we look at the classic biological definition of cancer, it is quite simply this: unregulated cellular proliferation. The mechanism that allows unregulated proliferation is a realignment of cellular circuitry for growth cues.
The genetic machinery is essentially altered to overproduce cell surface receptors, called growth factor receptors (GFRs). These antennas amplify and activate chemical signals that run along complex molecular pathways in the cancer cell to drive cancer cell growth and proliferation. Many cancer drugs we use today target these signaling pathways.
Some evidence shows that cannabinoid receptors are expressed on cancer cells, which supports the pharmacological basis for why cannabinoid receptor agonists (i.e., cannabinoids) could be effective for cancer. A cancer cell is trying to figure out ways to grow, so it puts its receptors on the cell, one of which happens to be cannabinoid receptors. The pharmacological action of a cannabinoid receptor agonist depends on the cell type, and in cancer cells, it may act as a trojan horse.
By current understanding, cannabinoids go through these receptors and activate the production of a compound called ceramide, which regulates the differentiation, proliferation, and death of cells. In cancer cells, and perhaps cancer stem cells, this effect is a broad system outage, shutting down cancerous signaling pathways; Several of these pathways are major targets in cancer drug development and are often specifically difficult-to-target pathways. This emerging understanding of the relationship between cancer cells, cannabinoids, and cannabinoid receptor agonists is advancing new ways to understand and treat cancer.
Cannabis can help beat cancer, as different types of cancer (but not all types of cancer) have endocannabinoid receptors. Phytocannabinoids can influence these receptors and give cancer cells the instructions to slow down growth or kill themselves. Terpenes and terpenoids also have anti-cancer properties.
There is little evidence that cannabis alone can help beat different types of cancer, and chemotherapy and radiation therapy are often still needed. Another thing to realize is that not all types of cancer have endocannabinoid receptors, so that cannabis may be ineffective. Moreover, the correct cannabinoid ratio must be used for some kinds of cancer, as the wrong one may either do nothing or even send a growth signal to cancer!
As cannabinoids can help dampen the immune system, chemo and radiotherapy also suppress the immune system, so doctors need to pay close attention to prevent infections that could cause death. Those undergoing immunotherapy should ideally avoid medical cannabis.
When it comes to appropriate treatment, should one use as many cannabinoids and terpenes as possible, in as high doses as possible, and utilize the entourage effect as much as possible (often used in the Rick Simpson method), or should specific profiles be used to beat specific cancers in as clinical a way as possible? Or perhaps we need to use a particular cannabinoid-terpenoid ratio and then flood the body to ensure the cannabinoids reach all cells in the body? Further research may answer these and other remaining questions.
Synthetic cannabinoids, despite their potential dangers, may also allow for an even greater degree of targeted cancer therapy. Until there is more research, we do not have any definite answers.
- Tetrahydrocannabinol (THC) and tetrahydrocannabinolic acid (THCA/THCa)
- Cannabidiol (CBD) and cannabidiolic acid (CBDA/CBDa)
- Tetrahydrocannabivarin (THCV)
- Cannabichromene (CBC)
- Cannabinol (CBN)
- Cannabigerol (CBG)
Arguably, all the cannabinoids and terpenes in cannabis could be helpful for cancer. However, some cancers may need specific profiles and dosages, for example, some types of breast cancer.
The effective ratio depends very much upon the type of cancer. Still, a wide range of cannabinoids is ideal as many have anti-cancer properties and work best in conjunction with one another. High THC may be needed, but not in all instances.
There is a lot of interest in well-tolerated ratios like THC:CBD 1:1, or CBD-rich ratios like THC:CBD 1:2 and above).
Terpenes and Terpenoids
Effective Ways of Taking Medical Cannabis for Cancer and Chemotherapy
Routes of Administration
A cannabis product or variety rich in CBD (like CBD oil) and beta-caryophyllene is ideal. THC can also enhance other cannabinoids’ anti-cancer activity via the entourage effect, providing pain and nausea relief. Phytocannabinoids like CBN have sedative effects that may improve the duration and quality of sleep.
- Inhalation (vaporizer, inhaler)
- Tincture (sublingual)
- Transdermal patch
- Topicals and salves
What are the Pros and Cons of Taking Medical Cannabis for Cancer and Chemotherapy?
- Cannabis can help treat the side effects of chemotherapy. The prescription drugs Marinol and Dronabinol are synthetic versions of THC designed for this purpose. However, synthetic THC can be much stronger than the THC derived from cannabis. There aren’t any other cannabinoids balancing the synthetic THC and improving its efficacy via the entourage effect. Many people find natural THC to be much more tolerable.
- Helps cancer patients manage pain, inflammation, nausea, improper sleep (insomnia and sleep apnea), and cachexia (wasting syndrome)
- Cannabis could kill cancer cells or tell them to slow down – cannabis could have significant anti-tumor properties.
- Some suggest that significant inflammation from an event in the past or diet may trigger cancer – cannabinoids may help prevent this inflammation, as many are potent anti-inflammatories.
- Terpenes like beta-caryophyllene (which is a cannabinoid as well), pinene, and humulene have significant anti-bacterial and anti-tumoral properties. They may also increase the efficacy of some chemotherapy drugs (e.g., paclitaxel).
- Though there is no proven link between smoking cannabis alone and lung cancer, it makes sense to perhaps avoid combusting any plant material and breathing the resulting smoke into your lungs. This is especially the case if you manage lung cancer and/or breathing problems.
- Those undergoing immunotherapy for cancer should avoid cannabinoid treatment due to cannabinoids’ dampening effect on the immune system.
- One of the side effects of chemotherapy is a suppressed immune system. Therefore, it is of utmost importance that your medication is as pathogen-free as possible – no fungus, mold, bacteria, or other microbes that may cause an infection.
- The cannabinoid profile, ratio, and dosage must match the cancer classification. If it does not match, cannabinoid treatment may be ineffective or even harmful.
Useful Anecdotal Information
Scientific Data Overview and Studies
- Total Studies = 350 (includes many different kinds of cancer)
- Positive Studies = 301
- Inconclusive Studies = 38
- Negative Studies = 11
- 134 Meta-Analyses (96 positive, 27 inconclusive, 11 negative); 54 Animal Studies (53 positive, 1 inconclusive); 2 Double-Blind Human Trials (both positive); 21 Human Trials (18 positive, 3 inconclusive); 139 Lab Studies (132 positive, 7 inconclusive)
- 92 studies include CBD (88 positive, 4 inconclusive); 8 studies include CBDA (all positive); 75 studies include THC (71 positive, 3 inconclusive, 1 negative); 5 studies include THCA (all positive); 3 studies include CBC (all positive); 8 study includes CBG (all positive); 3 studies include CBN (all positive); 3 studies include THCV (all positive)
- No. of Leafwell Patients (2021) = 1,431
- Possible Overall Efficacy: High, although this may depend on the type of cancer being treated or managed.
Quotes from Studies
“Cannabinoids are a large and important class of complex compounds that have a promising therapeutic potential for the treatment of variety of diseases, including cancer. In this review, we focused on studies that provided evidence for anticancer effects of plant-derived and synthetic cannabinoids and their potential mechanisms of action. Cannabinoids were able to effectively modulate tumor growth in different in vitro and in vivo cancer models, however, these anticancer effects appears to be dependent on cancer type and drug dose.” Dariš, Barbara et al. ‘Cannabinoids in cancer treatment: Therapeutic potential and legislation.’ Bosnian journal of basic medical sciences vol. 19,1 14-23. 12 Feb. 2019, doi:10.17305/bjbms.2018.3532
“CBD has demonstrated robust anti-proliferative and pro-apoptotic effects on a wide variety of cancer types both in cultured cancer cell lines and in mouse tumor models. In comparison, CBD generally has milder effects on normal cells from the same tissue/organ. The anti-tumor mechanisms vary based on tumor types, ranging from cell cycle arrest to autophagy, to cell death or in combination. In addition, CBD can also inhibit tumor migration, invasion, and neo-vascularization (Figure 5A), suggesting that CBD not only acts on tumor cells but can also affect the tumor microenvironment, for example by modulating infiltrating mesenchymal cells and immune cells. The dependency of CBD on the endocannabinoid receptors, CB1 and CB2, or the TRPV family of calcium channels, also varies, suggesting that CBD may have multiple cellular targets and/or different cellular targets in different tumors (Table 1). Mechanistically, CBD seems to disrupt the cellular redox homeostasis and induce a drastic increase of ROS and ER stress, which could then exert the cell cycle arrest, autophagy, and cell death effects (Figure 5A).” Seltzer, Emily S et al. ‘Cannabidiol (CBD) as a Promising Anti-Cancer Drug.’ Cancers vol. 12,11 3203. 30 Oct. 2020, doi:10.3390/cancers12113203
“There have been ten clinical trials on the use of inhaledCannabis in cancer patients that can be divided into two groups. In one group, four small studies assessed antiemetic activity, but each explored a different patient population and chemotherapy regimen. One study demonstrated no effect, the second study showed a positive effect versus placebo, and the report of the third study did not provide enough information to characterize the overall outcome as positive or neutral. Consequently, there are insufficient data to provide an overall level of evidence assessment for the use of Cannabis for chemotherapy-induced N/V. Apparently, there are no published controlled clinical trials on the use of inhaled Cannabis for other cancer-related or cancer treatment–related symptoms.” NIH National Cancer Institute.
There is plenty of evidence to show that medical cannabis can help manage the side effects of cancer and chemotherapy. THC extracts are available for prescription targeting this purpose in the U.S. and beyond. There is also evidence that medical cannabis and its constituent phytocannabinoids, terpenes, and flavonoids have anti-cancer and anti-tumoral properties. There are some clinical trials supporting cannabis’ cancer-killing effects, but trials with higher numbers of participants need to take place.
Note that the information in this article does not constitute medical advice.
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