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Cristina Sánchez, Ph.D.

With over 20 years of research experience on the antitumoral properties of medical cannabis, Cristina Sánchez, Ph.D., explains where we are in the research and how and why cannabis helps fight cancer.



The Highly: How did your interest in cannabis research begin?

Dr. Cristina Sanchez : I was doing my Ph.D. at Dr. Manuel Guzman’s lab. At that time, we were interested in studying the effect of cannabinoids on energy metabolism in astrocytes, cells that accompany neurons in the brain. At some point, we switched the cell model we were working with from healthy astrocytes to tumor astrocytes because they are easier and cheaper to work with, and we started observing antiproliferative responses. That was 20 years ago. Since then, we’ve been trying to describe the antitumor effects of cannabinoids and how they are produced.

TH: Where are we in the research?

CS: We have an extensive body of preclinical evidence showing that cannabinoids, mainly THC and CBD, produce anti-tumor responses in many different models of cancer. They induce the death of tumor cells—and only of tumor cells—and block the progression of cancer by hampering not just tumor growth but also tumor angiogenesis and metastasis. Importantly, we also know how these effects are produced—which molecules are involved, how they are regulated by cannabinoids, etc. What we need now, and we need it desperately, is clinical research, research conducted in actual patients, to corroborate that what we see in the lab is also produced in humans.

TH: How does cannabis help cancer patients?

CS: Cannabis can help cancer patients in many ways. It’s been known for years that it can be used to prevent the side effects of chemotherapy (nausea and vomiting), increase appetite, reduce anxiety, deal with pain, etc. Our research and that of other groups suggest that cannabis could also be part of the antitumor therapeutic toolbox, but clinical studies are needed to confirm this idea.

The fact that something is widely spread on social media doesn’t mean it is true. This is a warning call to the patients: Please go to reliable sources of information.

TH: Is it the THC or CBD or both?

CS: In preclinical studies, both THC and CBD have been shown to produce antitumor responses. In some models, THC is more potent. In others, it’s CBD, and in others, the combination of both. Since we don’t have results from clinical studies yet showing what is best for each cancer subtype, a good starting point for those wanting to incorporate cannabis into their treatments is to use both. The majority of the research on the anticancer effects of cannabinoids has been conducted with THC. Besides its own antitumor properties, CBD is also able to somehow buffer the psychoactive effects of THC, so the combination would be a good option to start with.

TH: Does it really shrink tumors?

CS: What we have observed in animal models of cancer is that the growth of the tumors is dramatically reduced. In some cases, we have observed a complete disappearance of the lesions, but in most cases, it is a reduction in tumor growth. We still don’t know if this happens in humans as well. There are many testimonials claiming that this is the case, but we do need clinical studies to answer this question categorically.

TH: Is there a type of administration people should try first?

CS: How much cannabis and how long it lasts in our bodies depends greatly on the route of administration. If a cancer patient is looking for an instant relief of a symptom—pain, nausea, etc.—vaporizing may be a good option. A high amount of cannabinoids will get to the organism very fast. The downside is that the effect will disappear soon. If the patient is looking for antitumor responses, although we still don’t know which are the appropriate doses to achieve this in humans, (s)he will want to have high levels of cannabinoids for as long as possible in her/his system, and that is best achieved via sublingual administration.

TH: How would we know our best dosage?

CS: Until we have clinical studies, I am afraid it is a question of trial and error. One option would be getting to the maximum tolerated dose: Start with very low doses and increase them very slowly until the patient reaches a dose that produces uncomfortable side effects. The only way to know if that dose is working would be to check the progression of the disease by analyzing the conventional cancer markers and imaging results.

I would like to mention here that the widely spread protocol of 1 g a day for three months has no scientific grounds. I am aware that many people on the internet recommend it, but it has no scientific support. First of all, why 1 g? Why 3 months? Where do these numbers come from? Second, 1 g a day of what? Cannabis preparations are very different. Some contain high levels of THC, others high levels of CBD. Some are very concentrated, others very diluted, etc. 1 g of a preparation without knowing its composition is exactly the same as saying nothing. Third, is it the same protocol for every type of cancer? The World Health Organization recognizes approximately 200 types of cancer. Is it reasonable to think that the same protocol would work for each of them? The fact that something is widely spread on social media doesn’t mean it is true. This is a warning call to the patients: Please go to reliable sources of information.

TH: Is it usually multiple applications or one?

CS: If we are talking about potential antitumor effects and assuming that a patient will require high doses of cannabinoids for a prolonged duration, multiple applications would be the choice. Ideally, the body would be loaded with cannabinoids all day long, and that is best achieved with several administrations throughout the day.

Until we have clinical studies, I am afraid it is a question of trial and error.

TH: Can I use it with my other meds?

CS: The preclinical research suggests that the combination of cannabinoids with standard chemo-/radiotherapy works even better than chemo-/radiotherapy or cannabinoids alone. In this case, there are many clinical studies available showing that patients undergoing chemotherapy can use cannabis at the same time to treat pain, nausea, vomiting, etc. and that this combinations does not affect the effectiveness of their medications. There are, however, a couple of things that should be taken into consideration, the main one being the fact that cannabinoids, mainly CBD, block a protein (cytochrome P450) that is in charge of degrading an important number of the medicines we take. Doctors should check this potential interaction to readjust doses.

TH: Are there any other ways you suggest we can help ourselves?

CS: My main suggestion would be always try to find a reliable source of information, products, and medical guidance. Since the medicinal use of cannabis is not fully regulated in most places, patients are unprotected and in many cases victims of scammers. Search for reliable sources of information. Unfortunately, most doctors don’t know much about the therapeutic potential of cannabis, but a few of them do. Go to the researchers. Go to the groups that guide patients in a professional manner, not just selling them products and not caring about their outcomes. Search for reliable sources of products. Always request lab test results to know what you have in your medicine—how much THC, CBD, etc.—and what you don’t have, which is equally important. Is it free of pesticides, heavy metals, bacteria, toxic solvents?

TH: Do you have a relationship with cannabis?

CS: I do have a professional relationship with it. My research is focused on cannabis, and I also use it sporadically in my private life.

TH: How do you use it? Does it help you?

CS: I use it at night, during the weekends. It helps me sleep and relax. It also makes me enjoy music in a very special way. I love music, and the way I feel it when I use cannabis is amazing. I also use Aunt Zelda’s cannabis-based topical for my face. I’ve had adult acne for years, and this is the only thing that has kept it under control.

TH: What other forms of wellness do you practice?

CS: I try to do exercise on a regular basis—three times a week—which includes walking. I used to run, but I’m currently recovering from a lesion. I also try to eat healthy, which in my country, Spain, is relatively easy.

TH: Your favorite saying?


On a personal note...


When my friend Inna was suffering from stage 4 colon cancer while raising her two young girls, the anxiety simply became too much. Luckily, the 2016 elections were a good distraction. Only after her pain and anxiety management failed, was she offered a cannabis pill in synthetic form.

Colon cancer and pills don’t mix after a while. Synthetic anything isn’t cannabis. Not to me.  When I visited a dispensary and asked for their very best, they gave me something made with corn syrup and sugar. This experience was one of the seeds that motivated me to uncover only the good places stocking the real stuff that I could proudly give to my friend.

I dedicate this interview to my mom, my friend Inna, and anyone who has lived with cancer or supported someone who has or has had it.

Let’s get the proper research underway. Call your representatives.


Hear more from Dr. Sanchez.