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Study Finds Cannabis Has Anti-Tumor Effects

A research review has concluded that marijuana has anti-tumor effects and is effective at reducing the pain, nausea, and vomiting induced by chemotherapy.

Researchers have found cannabis to be effective at inhibiting tumor growth and at reducing the severity of the symptoms commonly caused by chemotherapy treatments. In a research review, published in JAMA Oncology, Gianna Wilkie and a team of researchers from the Brown University Alpert Medical School of Brown University examined data from previous studies to summarize cannabis’s cancer-related therapeutic value and symptom relief.

“Cannabis in oncology may have potential in its use for anticipatory and refractory [cannabis-induced nausea and vomiting], refractory cancer pain, and as an antitumor agent,” Wilkie and her team concluded.

The researchers found both in vivo and in vitro studies that demonstrated cannabinoid’s ability to inhibit tumor growth by increasing cancer cell death and suppressing cell proliferation. The two major cannabinoids found in cannabis, tetrahydrocannabinol (THC) and cannabidiol (CBD) showed potential as antineoplastic agents.

In addition, the researchers found that numerous studies have shown cannabis to be effective at suppressing the nausea and vomiting related to chemotherapy. Cannabis reduces the frequency and severity of chemotherapy-induced nausea and vomiting (CINV), commonly the most distressing side effect of the treatment, as well as anticipatory nausea, which occurs before a new cycle of chemotherapy in response to the sights, smells, and sounds of the treatment room.

Several clinical trials found cannabis to be effective at relieving chronic cancer pain as well as neuropathic pain. One study even showed that a two-week treatment of cannabis containing both THC and CBD offered pain relief to cancer patients who had previously been unsuccessful in managing their discomfort with opioids.

Wilkie and her team also acknowledged that cannabinoids have shown to be safer compared to other analgesic medications like opioids.

“In the aforementioned studies, THC was seen to be more sedating than codeine but unlike opioids was not associated with respiratory depression,” the researchers wrote. “The extrapolated estimated lethal dose of cannabinoids from animal studies is approximately 680 kg smoked in 15 minutes, making overdose unlikely.”

While Wilkie and her research team concluded that studies have shown cannabis to have significant positive effects on cancer and chemotherapy-related symptoms, they did declare the need for more studies.

“More research is needed in all areas related to the therapeutic use of marijuana in oncology,” Wilkie wrote in the article’s abstract. “Currently, cannabis is not a primary means of treatment for any cancer or treatment-related adverse effect. However, as marijuana legalization, access, and research increases, this may change.”

Since 1996, 29 states and Washington D.C. have established medical marijuana legislation.

Learn more about what research has found about cannabis and cancer by visiting our education page.