In nearly 40 states, people are turning to cannabis for the relief of cancer-related symptoms, including pain, loss of appetite and the nausea and other discomforts caused by treatment. Many cancer patients say cannabis provides more relief than standard treatments, and recent studies have confirmed the effectiveness of cannabis for cancer symptoms. But there’s been a notable lack of the high-quality, large-scale studies with the potential to confirm the benefits of cannabis for cancer patients and survivors.
However, this is changing, thanks in part to a major joint study published in 2019 by the Journal of Oncology Practice. This research conducted by the Minnesota Department of Health and the Oncology Research Center at HealthPartners/Park Nicollet analyzed 1,120 cancer patients who participated in Minnesota’s medical marijuana program between July 1, 2015, and Dec. 31, 2017.
These patients self-reported the severity of their symptoms in eight different categories over a period of four months. Categories included the following:
- Nausea
- Pain
- Anxiety
- Vomiting
- Fatigue
- Depression
- Sleep issues
- Lack of appetite
While the results of this study largely confirm what has long been supported anecdotally, they’re especially important for a number of reasons, most notably due to the size and scope of the study.
The Scale of the Study Makes It Important to Cannabis Research
This study is hardly the first to indicate that cannabis can ease symptoms associated with cancer. The American Cancer Society points out that small studies have shown that cannabis may help with these symptoms:
- Neuropathic pain
- Loss of appetite
- Nausea and vomiting caused by chemotherapy
More recently, studies conducted on cells in a lab have found that cannabinoids like tetrahydrocannabinol (THC) and cannabidiol (CBD) can slow the growth of some types of cancer cells.
But many of these studies have focused on small patient populations. That’s what makes the Minnesota study different: It analyzed more than 1,000 patients.
What also sets this study apart is that a government agency helped conduct the study—in this case, the Minnesota Department of Health. Minnesota’s medical marijuana program is unique in that it requires participants to supply more information than other states do. This enables researchers to better track the effectiveness of the medical marijuana program through studies like this one.
Along with the scope of the study and the quantity of patient information available to researchers, the Minnesota study tracked eight different symptom categories. In comparison, smaller studies have analyzed just one or two specific symptoms. This approach gave researchers a more holistic view of the extent of symptom relief that participants experienced.
Study Limitations Affect Outcomes and Conclusions
Of course, the Minnesota study had some limitations. For one, symptom severity was self-reported, which makes the study prone to bias. Participants also tended to skew towards those who returned after a four-month period to obtain more cannabis. This could suggest that the study is biased towards patients who found relief with cannabis, while potentially overlooking those who didn’t feel that the plant effectively addressed their symptoms.
Many of the patients would also have been taking other treatments at the time. That made it impossible for researchers to determine when symptom relief was due to cannabis or whether it was due to other treatments, or a combination of the two.
Finally, types of cancers weren’t tracked, so researchers didn’t have an opportunity to determine if cannabis was more effective at relieving symptoms for specific types of cancers.
Despite these limitations, this study supports what many other, smaller studies have already found: Cannabis is an effective method of symptom relief for many cancer patients.
The Results Indicate That Cannabis Can Relieve Cancer Symptoms
Researchers in the Minnesota study found that cancer patients reported a significant reduction in their symptoms after taking medical marijuana for four months. The majority of patients in the study found relief from symptoms in all eight of the categories being studied. Although these symptoms didn’t disappear entirely, they tended to go from severe to moderate.
For pain relief, the findings were especially encouraging. Before taking part in the medical marijuana program, participants had a median pain score of eight on a 10-point scale (with 10 being the most severe pain).
After four months of taking cannabis, this score dropped to 6.7. Additionally, at the start of the study, 25 percent of patients reported a pain score of 10, but after four months of consuming medical marijuana, this percentage dropped to under 10 percent.
Vomiting also decreased substantially. About half of the participants who reported vomiting said that the severity of the vomiting decreased by about 30 percent over four months.
While side effects of taking cannabis were reported in about 11 percent of participants, these were generally mild and tended to include the following:
- Increased appetite
- Dry mouth
- Tiredness
More Research Is on the Horizon
Data from the Minnesota study can help to support the use of medical cannabis as a recognized part of cancer treatment. This study also lays groundwork for more large-scale studies on the effects of cannabis in cancer care. Topics for large-scale investigation include the use of cannabis for pain control in advanced cancer patients, since previous studies have already found that cannabis may be used as a potential substitute for highly addictive opioids. Other areas ripe for further study include cannabis as a treatment for cancer-related sleep problems, and more research on the effects of cannabis on the development of cancer itself.
