New study finds that cannabis may suppress immunotherapy for cancer patients

Sep 8, 2020

Although researchers, users, and especially the Food and Drug Administration debate the medical uses for cannabis, it’s widely agreed that the drug can help to alleviate many of the symptoms caused by cancer and chemotherapy, such as nausea, lack of appetite, and restlessness. A few years ago, when the National Academy of Science put out their massive report on medical cannabis, researchers agreed that the plant showed great promise in treating these particular ailments — which is not to be confused with the contention that cannabis can cure cancer, of which the jury is very much still out.

However, new research supported by the Israel Cancer Association, which was led by Israeli scientists Dr. Idan Cohen and Prof. Gil Bar Sela from the Oncology Department at HaEmek Medical Center in Afula, along with Prof. Dedi Meiri from the Rappaport Faculty of Medicine at the Technion found that while cannabis may help to alleviate symptoms caused by cancer treatments, it might interfere with immunotherapy designed to treat the cancer itself.

According to a report in The Jerusalem Post, the new study found that cannabis did, in fact, relieve patients suffering from some of the worst side effects of cancer treatment. However, researchers found a correlation between cannabis use and the amount of time until the cancer spread, with higher rates of use equaling a shorter incubation period for the disease. 

Patient survival rates also worsened dramatically, according to the study.

According to the Jerusalem Post, Immunotherapy is one of the latest breakthroughs in the field of cancer treatments. A patient’s immune system is used to detect and attack cancer cells. It has been found to be extremely effective.

"The Israel Cancer Association recognizes the importance of research in the field of cancer, and each year provides support and funding for dozens of leading studies selected by the association's research committee," said ICA director-general Moshe Bar-Haim, according to The Jerusalem Post.

According to Prof. Bar Sela, cannabis suppresses the immune system in the same way that steroids do.

“There is a laboratory study that suggests that cannabis suppresses the components of the immune system that are activated by immunotherapy," said Prof. Bar Sela, according to the Jerusalem Post. 

The professor also noted that "steroids also suppress the immune system, so it is recommended not to start immunotherapy if you are taking moderate-dose or higher steroids regularly" and that "it may be worth giving a similar recommendation regarding cannabis as well."

"That is, if at the starting point of immunotherapy treatment, the body is under the influence of cannabis, the immune system is probably suppressed to some degree and the success of immunotherapy may be impaired," he added.

While the study does have limitations — researchers only looked at 102 patients with advanced cancer who started immunotherapy, with 68 who used cannabis and 34 who did not — the results did confirm the finding of a previous study done in 2014 by Prof. Bar Sela.

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