Cannabis as Cancer Therapy – A Metastudy That Is Not and Misrepresents the Situation

Cannabis and Cancer: Study Biases and Conflicts of Interest

Then, one should also look at the potential biases related to the financing of this analysis.

The analysis itself was financed by the Cancer Playbook organization. And that's not strange, sometimes associations get money from donations that finance the research they need. But when you look at their site, you will see that they promote the treatment of oncological diseases in humans and dogs using cannabis preparations, they advocate plant-based medicine, which is ok, but here it is a synonym for cannabis (full extract of cannabis oil – FECO) and last but not least – they promote treatment using sounds of certain frequencies, which is a pseudoscientific method. So, they commissioned a study that would fit their narrative and sales aspirations.

Another problematic point is that one of the authors of the “meta-analysis”, William C Bushell, is from the Chopra Foundation – yes, Deepak Chopra's foundation, which promotes quantum medicine, alternative medicine and various other pseudoscience.

None of this has been stated as a conflict of interest.

Science Doesn’t Fulfill Wishes. It Doesn’t Prove What We Set Out to Want. That’s What Pseudoscience Does.

Science does not do this – it does not create research to match what some scientist has imagined. The research is not there to confirm the initial thesis. It is there to be refuted or confirmed. We don't set up evidence to suit our needs. And we cannot write that the keyword analysis is a meta-analysis that proves that there is more and more evidence of the usefulness of cannabis in cancer therapy.

The study showed what is already well known – that cannabis and its derivatives have a certain value in palliative care, that they reduce pain, and that they can increase appetite in patients and reduce nausea during chemotherapy. Also, it has been shown here that some studies have evidence that cannabinoids improve sleep in patients. However, it should be added that there are more efficient means for all that.

Here's what this “meta-analysis” looks like in reality :

Thus, the authors themselves admit that they mixed studies with different methodologies and different levels of evidence, and that some of these studies do not provide evidence for the usefulness of cannabis and its derivatives, and that some are limited and insufficient.

The study claims that there is strong evidence for effectiveness in cancer therapy. However, when you read that subtitle, all it says is that 70-90% of patients in one study reported feeling better, which is subjective rather than objective evidence. Then “ meta-analysis” again mixes preclinical and clinical studies, which is unacceptable. Thus, he compares the results of preclinical studies (these are studies on animals and cell cultures) as they found that cannabis derivatives cause apoptosis (cell death, which is certainly welcome when it comes to cancer cells) and inhibit the growth of tumor cells, and then he says that clinical studies show that cannabinoids are good in the management of nausea and increase appetite in patients. Therefore, preclinical studies of the effect of cannabinoids on apoptosis and observational studies of the effect on reducing nausea and increasing appetite are cited side by side as an equal level of evidence. Different methods and different goals.

The study referred to by the authors of this “meta-analysis” related to apoptosis “Anticancer mechanisms of cannabinoids” (2) is actually a review paper in which the results of a series of studies are collected and commented. The authors themselves write here that there are some preclinical studies that cannabinoids work to control angiogenesis (the creation of new blood vessels that feed the tumor) and have an antitumor effect, watch out for this – on cell cultures of genetically modified mice, but also that there are studies that show that cannabinoids can induce cancer. Although cell culture studies are very important, they are only the beginning level, a signal that something needs to be investigated, not a strong proof. In such conditions, alcohol also acts to slow down tumor growth.

We should not leave out the fact that the consumption of cannabis (specifically smoking marijuana) increases the risk of throat cancer. Those who smoke marijuana have a 2.5 times increased risk of developing oropharyngeal cancer. Smoking marijuana also accelerates the development of cancer in the head and neck area caused by HPV (14).

Cannabis and cannabinoids have side effects that are reported in the studies considered in this meta-analysis – such as paranoia. A strong level of evidence indicates that cannabinoids are associated with an increased risk of psychiatric disorders (3, 4), including schizophrenia, psychosis, and this risk is greater if a person uses cannabis and cannabinoids in adolescence (5).

Children of mothers who consumed cannabis and its derivatives during pregnancy have a higher risk of neurodevelopmental disorders and attention disorders, and the risk for the child's development is also the father's use of cannabis, through epigenetic mechanisms that change the activity of genes in sperm (6,7). This has been shown by studies on mice that can be translated to humans as well (8).

Exposure of the fetus to THC is associated with lower birth weight (9) and the appearance of various disorders and defects (10). Marijuana smoking is associated with a moderate increase in the risk of some forms of cancer (11).

Cohort studies on a small number of patients show a reduction in depression and anxiety, as well as headaches (13), which could also have a somewhat positive effect on cancer patients, but even here there are far more effective medications, anxiolytics and antidepressants that can better help in this life struggle.

There is some evidence for suppression of intestinal tumors by cannabinoids (15), but more research is needed.

There are a number of studies showing that cannabinoids reduce nausea, increase appetite, help with pain management in cancer patients, such as this systematic review and meta-analysis (12).

The aforementioned study did not initially address the impact of cannabis and its derivatives on the treatment of multiple sclerosis. Here too, the data is mixed and inconclusive.

According to the Society for Cancer Research UK, claims that there is solid evidence for the use of cannabis and its derivatives in the therapy of cancer patients are very wrong.