Medical Cannabis for Symptom Relief in Cancer

Cancer is one of the most prevalent diseases on the planet and a leading cause of death. The National Cancer Institute estimates that there were 14 million new cases worldwide in 2012, with 8.2 million deaths. Worse, the number of new cases per year is rising, potentially reaching 21 million per year by 2030. 

One reason cancer is so deadly is because it is very difficult to treat. In essence, current chemotherapy regimens involve poisoning every cell in the hope that the malignant ones die out first. The painful irony of this is that chemotherapy treatments can be as bad or worse than the disease, causing severe pain, nausea, dizziness, vomiting, and other debilitating side effects.

Currently, the treatment option of choice for pain management is opioid drugs. These compounds form the basis of many prescription drugs, such as Oxycodone, Percocet, morphine, codein, and fentanyl. While these compounds provide powerful pain relief, the body begins to tolerate them over time, requiring higher and higher doses to get the same effects. Higher doses lead to negative side effects, like constipation, nausea, and sleepiness. There is also the well-documented risk of addiction and physical dependence. Given this situation, there is a real need for effective palliative care that presents less of a risk for patients.

Increasingly, cannabis is being prescribed for just this purpose. Multiple studies have shown that cannabis provides effective palliative care for cancer patients. A recent report published in the European Journal of Internal Medicine by a group of Israeli researchers details the experiences of cancer patients using medical cannabis. This observational study shows the difference that medical cannabis can make for those looking for better palliative care.


Patients were recruited from Tikun-Olan Ltd., the largest medical cannabis distributor in Israel, during the approximately two year period between March 2015 and Feb. 2017. Patients entering the clinic were given an educational orientation session, then asked to take a survey. This initial survey asked patients to describe their current symptoms and pain intensity on a ten-point scale. The researchers then administered follow-up surveys at one and six months after initiating cannabis treatment. Patients were asked about their symptoms and severity, side effects from their cannabis medication, and their overall quality of life. The researchers defined “treatment success” as those who stuck with their cannabis treatment for all six months, did not experience serious side effects, and self-reported at least “moderate improvement” in their quality of life. 

One month after beginning treatment, the majority (85.8%) of patients reported at least moderate improvements in life quality. Further, only ~6% of respondents experienced side effects, and <10% said that the cannabis did not help them.

At six months, the results were even more dramatic. Prior to treatment, over 50% of patients rated their as severe (8-10 on the scale). Six months later, that number dropped to 4.6%. Overall quality of life was greatly improved, with ~70% of patients describing their lives as “good”. Based on their definition of “success,” ~60% of their patients had successful treatment from medical cannabis.

In addition to pain relief, medical cannabis use was associated with improvements in a number of other symptoms. The most improved symptoms were nausea and vomiting, restlessness, headaches, sleep disorders, anxiety and depression, and pruritus (severe itching). Compare this to 18.7% prior to treatment.

While the majority of patients had positive experiences with their cannabis treatment, nearly a third experienced unwanted side effects. The most common was dizziness, followed by sleepiness, increased appetite, dry mouth, and “psychoactive effect”. Out of 1,742 patients who responded to all surveys, only 290 stopped their treatment. Of that number, 28% stopped because it was no longer needed, and 22% stopped because it had no apparent effect. This demonstrates the relatively mild and manageable side effects that come with medical cannabis use. 


While these results are promising, it’s important to keep several factors in mind. First, this is an observational study, meaning all results are correlations. For any given patient, it is possible that symptom intensity decreased simply because they got better, and that this was completely unrelated to the cannabis treatment. Self-reported surveys like this are subjective in nature, and are often unreliable. There is also a selection bias at play. These patients had already chosen medical cannabis for treatment, and may be more likely to have positive feelings towards cannabis use, further skewing their survey answers. Finally, several of the authors are employees of Tikun-Olan Ltd., including the study designer, who is on their scientific advisory board.

That said, there are promising trends in the data that are hard to overlook. In addition to symptom relief, patients reported dropping other medications they were taking. Nearly half of the patients who were taking opioids or other analgesics at intake either stopped taking them or reduced their dose. The dramatic drop in pain ratings and increase in quality of life are hard to dismiss, especially with such a large sample size. The incidence of cannabis-related side effects was quite low, and most were mild and well-tolerated. The results of this study point to medical cannabis as a potentially powerful alternative to opioids for pain management.

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