The effects of cannabinoids appear to be very complicated and difficult to interpret and, above all, extrapolate: there are also a number of studies that show that these substances actually stimulate cancer cells to multiply and spread further.
Effects of cannabinoids have also been found on cells of the immune system. The same applies here too: different cell and animal studies produce conflicting results, for example there are studies that show that cannabinoids actually inhibit the tumor-suppressing effect of their own immune system. The latter has also been demonstrated recently in a clinical study in patients.
The scientific literature shows that the mechanism of action of cannabinoids in cancer is extremely complicated and dependent on many different variables. It is of course interesting to know whether cannabinoids can have effects on cancer cells in a test tube or animal mouse. However, this does not mean that these agents are effective, applicable and safe in humans. There are many scientific steps between the laboratory and application in humans.
To date, only one study has been conducted in cancer patients, the results of which have been published in a scientific journal. More than ten years ago, Spanish researchers injected nine pure THC patients into the brain tumor. The drug did not cause extreme side effects, but all patients died within one year after the treatment. This fits in with life expectancy with this very aggressive form of cancer. Injecting THC directly into the brain into the tumor tissue is miles away from oral administration of cannabis oil. The conclusion is therefore justified that there are currently no clinical studies that show that pure cannabinoids, let alone 10% cbd oil for pain, have any effect against cancer.
In November 2017, the US Food and Drug Administration (FDA) officially warned consumers about CBD and THC products that claim to work against cancer and called these claims “unproven and misleading.”
Safety and side effects
Many cancer patients use cannabis oil, often in combination with regular chemotherapy, under the motto ‘it doesn’t help, it won’t harm’. However, cannabis oil is certainly not completely safe. Patients in particular report frequent short-term side effects: gloomy mood, restlessness and insomnia, dizziness, drowsiness, hallucinations, palpitations and dry mouth.
Cannabis can also provoke or aggravate psychological symptoms such as psychoses and schizophrenia and heart complaints such as angina pectoris. If cannabis oil is taken at the same time as regular medicines or chemotherapy, there is a risk that THC and CBD will influence the exposure and the effect of that chemotherapy.
In the literature , such interactions are described in laboratory tests, where THC influences the action of certain transport proteins that drugs work out of the body. THC would thus increase the toxicity of chemotherapy. However, good clinical research is also lacking here. The literature also describes interactions between cannabis and drugs such as antidepressants.
Cannabis suppresses the functioning of the immune system and this can have a major negative effect on the regular cancer therapies that are often based on immunological effects. A recent retrospective study shows that combining regular immunotherapy (nivolumab) with cannabis results in a twice as low response to therapy compared to immunotherapy without cannabis.