In dozens of states, people consume medical marijuana to help ease symptoms related to cancer and chemotherapy, such as nausea, loss of appetite, dizziness and pain. While research has backed up cannabis’s effectiveness in helping cancer patients find relief, high-quality, large-scale studies are still lacking.
However, this is changing thanks in part to a major joint study that was recently published in the Journal of Oncology Practice. The Minnesota Department of Health and the Oncology Research Center at HealthPartners/Park Nicollet conducted the study and found that cancer patients reported a significant reduction in their symptoms after taking medical marijuana for four months.
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 study 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, and the results were tracked over a period of four months. Categories included:
Researchers noted that symptoms eased in all eight categories. While symptoms didn’t disappear entirely, they tended to go from severe to moderate.
In terms of 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% of patients reported a pain score of 10, but after four months of consuming medical marijuana, this percentage dropped to under 10%.
Vomiting also decreased substantially. About half of the participants who reported vomiting said that the severity of the vomiting decreased by about 30% over four months. While side effects were reported in about 11% of participants, these were generally mild and tended to include:
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 marijuana may:
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.
However, many of these studies have focused on small 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.
Meanwhile, the study tracked eight different symptom categories, while smaller studies have only analyzed just the one or two symptoms. This approach gave researchers a more holistic view of the extent of symptom-relief that participants experienced.
Also, the vast majority of the Minnesota participants consumed high-THC products, with just 1% taking high-CBD products. This adds to the growing body of evidence that THC—not just CBD—has plenty of its own health benefits.
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. It was impossible for researchers to determine when symptom relief was due to cannabis or whether it was due to other treatments.
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 studies have already found: that cannabis is an effective method of symptom-relief for many cancer patients.
The researchers are planning on following up their work with another study, which will analyze how cannabis affects pain control and opioid use in patients with advanced cancers. Preliminary results from this study are expected in June 2019.
Previous studies have already found that marijuana may be used as a potential substitute for highly addictive opioids. Combined with cannabis’s effectiveness at helping cancer patients find relief, it’s becoming increasingly clear that this plant has myriad potential health benefits that we’re still only beginning to understand.
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