Medical use of marijuana and cannabis is widespread. But scientific evidence of its efficacy against many symptoms of cancer is incomplete. Leading cancer expert discusses his research on cannabis efficacy in alleviating cancer symptoms. Can cannabis alleviate side effects of cancer treatment?

Dr. Anton Titov, MD. You study the medical effects of marijuana use. Dr. Anton Titov, MD. You study perceived efficacy and side effects of marijuana use in people who are being treated for cancer. What did your studies show? Dr. Anton Titov, MD. We look at clinical data regarding treatment with medical cannabis simply because in Israel many cancer patients received cannabis treatment. It is legal in Israel and it is supplied. Patients get permits from the Ministry of Health. Dr. Ido Wolf, MD. We try to see how medical cannabis. First of all, if it is effective at all. How patients take it, how they define if it is beneficial or not. This is important because there is not too much kind of evidence-based data about medical cannabis. There are no Phase 3 trials, for example, that show whether marijuana is effective or not. Dr. Ido Wolf, MD. What we do, we simply go and ask the patients. We try to go through the medical files and see what happened to those who took or did not take medical cannabis. We see that marijuana is effective in some patients. It is affecting mostly symptoms. We don't think that marijuana affects cancer progression. I don't think that it is a good cancer therapy. But it can definitely help some patients, for example, by alleviating pain, acting against nausea and vomiting. Dr. Ido Wolf, MD. There are some symptoms that can be positively affected by using medical cannabis. It is good to some of the patients, but not all of them. Some patients take the cannabis and it causes them side effects, especially the elderly. Cannabis can cause some dizziness, sometimes making walk unstable. But we know that for some patients cannabis is a very good palliative medication. We looked at cancer patients who received the cannabis from their oncologists, mostly for palliation. We saw that in about half of the patients cannabis helps them mostly in the palliative setting. Dr. Ido Wolf, MD. That means less pain, less nausea and vomiting, sometimes cannabis helps with loss of appetite. We don't think that marijuana is a good treatment against cancer itself. But it can sometimes help to improve the quality of life of cancer patients.