Cancer is probably one of the main focuses when it comes to researching the effects of medical cannabis. One of the reasons for this is because cancer is a condition that affects millions of people in different ways – whether it’s the brain, blood or bladder. The other reason is because the plight of cancer patients is one of the biggest triggers for the legalization of medical marijuana and hemp, especially in the 70s and 80s. (Glaucoma, epilepsy and AIDS/HIV were others.)
Cancer is a group of diseases that involves abnormal cell growth that potentially spreads or invades other areas of the body. Signs include abnormal breathing, prolonged coughing, unexplained weight loss, a change in bowel movements and unexplained bleeding. Tobacco use causes approximately 22% of all cancers, 10% are due to obesity, lack of exercise and poor nutrition, and around 5% – 10% develop due to inheritance. In the developing world 20% of all cancers are due to infections such as hepatitis B, hepatitis C and human papillomavirus infection (HPI). Exposure to high amounts of ionizing radiation or heavy industrial pollutants are other risk factors.
In 2015, around 90.5 million people worldwide had cancer, and around 14.1 million new cancer cases are discovered each year. Approximately 8.8 million deaths per year worldwide are due to cancer. The most common types of cancer amongst males are lung, prostate, colorectal and stomach. The most common types of cancer amongst females are breast, colorectal, lung and cervical cancer. In the US, the five-year survival rate for children under 15 diagnosed with cancer is 66%. In the developed world at large, the survival rate for children under 15 diagnosed with cancer is 80%.
Lots of people ask us, “How does cannabis help with cancer?” We perhaps can’t explain it better than Dr. Michael Masterman-Smith:
In order to answer this we have to look at some basic tenets of cancer biology and how cancer cells mutate to stay alive and proliferate as cancer cells. If we look at the classic biological definition of cancer, it is “unregulated cellular proliferation. The mechanisms that allow unregulated proliferation is a realigning of cellular circuitry to for growth cues.
The genetic machinery is essentially altered to overproduce cell surface receptors, called growth factor receptors. These are antennas which amplify and activate chemical signals that run along complex molecular pathways in the cancer cell to drive cancer cell growth and proliferation. Many cancer cancer drugs we use today target these signalling pathways.
There is some evidence to show that cannabinoid receptors are expressed on cancer cells. This 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. In cancer cells it may be like a trojan horse.
Current understanding appears that cannabinoids goes through these receptor and activates 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 widestream system outage, shutting down cancerous signalling pathways, several of which are major targets in cancer drug development and, often difficult to target pathways, I might add.
This is the emerging understanding of the relationship between cancer cells, cannabinoids and cannabinoid receptor agonists that can advance new ways to understand and treat cancer.”
One of the main theories behind using cannabis for cancer is using specific cannabinoid-terpenoid profiles for specific cancers and specific endocannabinoid systems (ECSs) as a form of “phytochemical therapy” as an adjunct to chemotherapy and radiotherapy. Another theory is the “Rick Simpson” method, which is essentially “flooding” the body with high doses of cannabinoids and terpenoids and preventing metastasizing of cancer cells in the body, regardless of where they are. However, there is anecdotal evidence that certain cancers respond better to certain cannabinoid profiles than others, and according to some, Treatment Must Match Classification as certain profiles may help cancer cells proliferate.
Cannabis seems to work for so many cancer patients because it not only helps manage the side-effects of chemotherapy, but may also help battle cancer of many types, including: bladder, brain, breast, colon, endocrine, kaposi sarcoma, leukemia, lung, prostate and skin. For research into the use of cannabis for cancer in general (and specific types of cancer as well), the following studies show some promise:
- Cannabidiol as potential anticancer drug
- The influence of biomechanical properties and cannabinoids on tumor invasion
- 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