cristina sanchez medical cannabis

"Cannabinoids may become a therapeutic tool in the service of oncology patients"

  • Cristina Sanchez is Professor of Biochemistry and Molecular Biology at the Complutense University of Madrid.
  • Founding member of the Spanish Observatory of Medical Cannabis, Dr. Sanchez has dedicated her career to the research of the applications of cannabinoids in the treatment of cancer.
  • We spoke to her about her research and on the current situation of cancer patients, who must resort to the black market or self-cultivation to access the cannabis they need to relieve their ailments.
cristina sanchez medical cannabis

You graduated and received a Biology degree from the Complutense University of Madrid in 1994. Did you think back then that you would end up focusing your research in cannabinoids? How did it come about?

I was on my third year of the Biology degree at the Complutense, and I was already aware that I wanted to pursue scientific research. I started looking for laboratories that accepted student collaborators and this is how I met Jose Antonio Ramos and Javier Fernandez Ruiz, from the Faculty of Medicine of the same University. At that time, they were one of the very few groups (if not the only one) working with cannabinoids in Spain. The time I spent with them confirmed that scientific research was my career goal, and I discovered a very interesting group of substances of which I had no prior information: cannabinoids. Once I graduated I joined Manuel Guzman's group to do my Grade Thesis first and my Doctoral Thesis later, both focused on cannabinoids. Although I have always enjoyed my work, passion for these compounds came with the early works in which we described their antitumor effect.

There is much controversy about cannabinoids and their ability to treat or cure cancer. Has it been scientifically demonstrated that cannabinoids have anti-tumour properties?

It has been tested in preclinical models, i.e. in tumour cells that are grown on plastic dishes and in animal models of cancer. In humans, unfortunately, we have not yet carried out controlled studies to allow us to say that what we have observed in the laboratory occurs in actual patients. We know that the Internet is full of testimonials from people who claim to have cured their cancer with cannabis, but unfortunately these testimonies have very limited clinical value because in most cases we do not know what the patients have taken exactly (what cannabinoids, how much , etc.), if they were also subjected to conventional treatments, etc. That said, it has been clearly demonstrated that cancer patients can get many benefits from marijuana: it helps combat the side effects of chemotherapy (nausea, vomiting, loss of appetite), it is an anxiolytic, and analgesic, it helps sleep, etc. Whether it also has anti-tumour effects or not, we still don't know, but it is also clear that its safety profile is very high, so if we place its benefits (actual and potential) on one dish of the balance and the risks on the opposite, the balance will, in the vast majority of cases, tip to the first.

Some patients can't afford to wait for pharmaceutical companies to produce their cannabis drugs

Do you think that in the near future cannabinoids will be used for the treatment of cancer?

If we succeed at demonstrating that they do have some effects on human tumours, yes. I sincerely don't believe that they will be the cure for cancer (I am afraid we will never find anything that is), but I am convinced that they can become a therapeutic resource for cancer patients. To accelerate this process, we need more clinical trials to be made, and to exploit all relevant clinical information, which right now we are throwing away.

There are hundreds of thousands of cancer patients around the world who have followed and are following treatments that include cannabis. If we could make a serious follow-up of these patients (which products do they use, what amount of the main cannabinoids are they consuming, what is the evolution of their illness ...) we would have much more information on the possible anti-tumour effects of cannabis in humans. For this reason, it is essential for patients to have access to products that have been analysed in terms of quality (cannabinoids composition) and, of course, of safety (absence of pesticides, heavy metals, toxic solvents, bacteria, etc.), and to have counselling and medical follow-up during the whole process. Obviously, this can only be achieved by legalizing and regulating the medical use of marijuana.

Do you think that there may be pressure from the pharmaceutical industry not to investigate or apply the medicinal properties of cannabinoids? Why?

I do not know if there is pressure or not from the pharmaceutical sector, but I sense they are "worried" by the peculiarities of these compounds. While it is true that there is an authorized drug based on cannabinoids in Spain (Sativex), it is only covered by the Social Security system to control spasticity in patients with multiple sclerosis who have not responded to conventional therapies. The remaining patients, who could benefit from this drug, potentially including patients with chronic pain, gastrointestinal inflammatory diseases, refractory epilepsies or cancer among other, would have to go through a real treasure hunt to have access to this product as compassionate medicine. If they finally succeeded (which is not easy), they would have to pay for it themselves and it is important to say that this product is extremely expensive. In this situation, patients have decided not to wait for further clinical trials (which are what give the green light to the use of drugs produced by pharmaceutical companies) and have begun to use products generated by other suppliers. This is what I mean when I speak of the "peculiarities" of these compounds: virtually anyone can produce their own medicine, and this makes the pharmaceutical companies become very restless.

Is it not risky for patients to be forced to buy cannabis without a medical check on the product type or the quantity used?

I personally don't believe that neither self-cultivation of marijuana nor uncontrolled sources of cannabis products are the best solution for patients with chronic and severe diseases. These patients should be protected and should know what they are taking: how much THC or CBD and that they are not ingesting heavy metals, pesticides, etc., as with any other medicine. This is why controlled products are needed, whether they come from large pharmaceutical companies or small producers. That said, I am also aware that patients can't wait for this to happen. They have pain already, they have epileptic seizures already and they see that the preparations they have access to, work. How are we going to tell parents not to give cannabis to their child with epilepsy until Epidiolex is approved, if they are already realizing that the marijuana preparations they are using is working for them? Neither those parents, nor the doctors, nor us as basic researchers, believe that these preparations are the best solution, but these patients can't afford to wait for pharmaceutical companies to produce their cannabis drugs. We need them, of course, but we need them now and at a price that is affordable for everyone; ideally covered by the Social Security system, like any other drug.

I think the Spanish State does not invest enough in research

Do you think the Spanish government is investing enough in medical cannabis research? Why?

I think the Spanish State does not invest enough in research. Full stop. In the case of research on the medicinal properties of marijuana, I would make a division between preclinical research and clinical research. We, for example, as a group of basic research, have never had trouble finding funding for our projects. We have been receiving uninterrupted financing for 20 years from the Ministry of Economy and Competitiveness, Education and Science (and all its variants with different governments), Health and private foundations (Spanish Association against Cancer, Mutua Madrileña, Sandra Ibarra Foundation, etc.). We've never encountered obstacles to investigate the therapeutic properties of cannabis, and I think my colleague researchers in other fields would say something similar. We all have trouble finding funds to investigate, but it isn't harder for us because of working on cannabinoids. Another thing is clinical research. Here there are more problems. First, because public resources for such studies (not only cannabinoids) are extremely limited; and second because of the administrative red tape associated with working with these compounds, which are still legally considered as dangerous drugs, without therapeutic properties and with a high addictive potential which−something which, by the way, has no scientific basis. All this makes it very cumbersome to embark oneself on a study of this type.

Cancer seems to be the silent epidemic of the XXI century. According to WHO over the next two decades an increase of 70% of patients is expected. What's going on? What are we doing wrong?

It is a reality that the incidence of cancer is increasing, especially in first world countries. I would not speak of guilt, but it is true that there are certain habits of the Western culture that are associated with a greater likelihood of developing cancer throughout life: a caloric imbalance (calorie diets, sedentary lifestyle), exposure to pollutants that are carcinogenic, stress, etc. On the other hand, although it sounds strange, there are general positive aspects that make the number of cancer patients in the world to grow: first, we live longer and longer, and the oldest our machines, our bodies, are, the less efficient the repair systems that prevent tumours become. In addition, cancer treatments are in some cases managing to turn the disease into a chronic one. Some types of tumours that were lethal some years ago are now kept under control with the right therapies.

Is a body with a strong immune system less prone to cancer?

I would say that in general, an organism with a strong immune system is more effective in preventing the onset and progression of cancer. Our body has several defence systems against the generation or growth of tumours. One of them is the repair systems I spoke about before, and another very important one is our immune system.

What true is there in the theories that claim that an alkaline diet can prevent the formation of cancerous tumours?

I'm afraid that the scientific basis behind this statement is not very solid. In principle, the argument put forward by the proponents of this theory is that tumour cells are in an acidic environment (which is true, due to their high metabolic activity), and they believe that alkalizing our fluids would eliminate them. In this respect, there are studies performed with tumour cells in culture showing that they do not survive in a medium with a high pH (alkaline medium). However, the acid pH environment of tumour cells is a consequence, not a cause, of tumour activity, and the studies I mentioned in cultures have not been replicated, as far as I know, in complex organisms: laboratory animals or humans. Alkaline diets may have some health benefits, but I fear that there is no scientific basis for claiming that they prevent or cure cancer.

A body with a strong immune system is more effective in preventing the onset and progression of cancer

What everyday habits would you recommend to the population to prevent cancer?

A healthy diet, exercise, avoid exposure to radiation and carcinogenic pollutants, reduce stress, etc., and regular check-ups: cancer-related mortality has generally declined in recent years in part due to improved therapies, but mostly due to early diagnosis. I'm not saying you have to do a CAT scan of the whole body every 6 months, but annual visits to a gynaecologist, urologist or family doctor to get a blood test, can help detect a problem in the beginning, when it is much easier to solve.


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