The “largest ever meta-analysis” of medical marijuana and its effect on cancer symptoms was published this week by researchers. They found “overwhelming consensus” in the scientific community about cannabis’ therapeutic benefits.
The study, published in the journal Frontiers in Oncology, analyzed data from 10,641 peer-reviewed studies—what authors say is more than ten times the number in the next-largest review on the topic. The study says that the results “indicate an increasing consensus among scientists regarding cannabis’ therapeutic benefits, particularly in cancer.”
The report describes the state of medical marijuana research as “scattered” and “hybrid”. Authors aimed to assess “the existing literature about medical cannabis, with a focus on its therapeutic potency, safety profiles and role in the treatment of cancer.”
“We expected controversy. In a press release, Ryan Castle, the lead author and head of research for Whole Health Oncology Institute said that they found a scientific consensus. This is the most convincing and dramatic proof of medical marijuana’s effectiveness in the treatment of cancer that has been seen by the scientific community.
According to a Whole Health Oncology Institute press release “The meta-analysis revealed that, for every study that demonstrated cannabis as ineffective there were three other studies which proved that it was effective.” “That 3:1 ratio—especially in a field as rigorous as biomedical research—isn’t just unusual, it’s extraordinary.”
According to the institute, “the level of agreement found here is comparable or even exceeds many other institutions.” [Food and Drug Administration]-approved medications.”
Researchers said that the strong scientific consensus in favor of the therapeutic use cannabis in cancer treatment suggests there’s a solid basis to reevaluate cannabis’ classification and legal status as Schedule I substances.
The findings suggest that cannabis has a high therapeutic potential. This is especially true for cancer symptoms, and it may even have anticarcinogenic effect.
Authors wrote in the study that the findings “have implications for public health research, clinical practice, and discussions surrounding the legal status of medical cannabis,” noting that the “consistency of positive sentiments across a wide range of studies suggests that cannabis should be re-evaluated within the medical community as a treatment option.”
While the analysis looked at a wide-range of cancer-related data, the four-person research team—from the Hawaii-based Whole Health Oncology Institute and The Chopra Foundation in New York—highlighted some key findings in their press release.
As an example, it was found that cannabis increased cancer cell natural death, reduced cancer proliferation, and limited cancer spread by blocking metastasis. In the same release, cannabis was described as having a “profoundly anti-inflammatory” effect. This is important because inflammation can be linked with over 80% the most chronic and debilitating conditions in the world.
Cannabis is well known for its role in treating cancer symptoms and it may also have anticancer effects that are both direct and indirectly.
Researchers used sentiment analysis—a method aimed at determining the tone of a text—to identify “correlations between cannabis use and supported, not supported, and unclear sentiments across multiple categories, including cancer dynamics, health metrics, and cancer treatments,” the study says. Results revealed a consensus that supported the use medical cannabis for cancer treatments and health metrics.
The report states that “the analysis highlighted the anticarcinogenic potential of cannabis and its use to manage cancer-related symptoms, such as nausea and pain.” It also explored “the consensus on its usage as an anticarcinogenic drug.”
At one point, it observes “that the consistent pattern between cannabis and cancer treatment suggests that there is a reasonable consensus among experts that the medical benefits of cannabis far outweigh any risks.”
The analysis concluded that the support for medical marijuana in published research was 31,38 times greater than the opposition.
They acknowledged possible limitations of the findings. For example, computer-aided emotional analysis. The authors wrote: “Algorithms may struggle with ambiguity and context-dependent meanings. This can lead to possible misinterpretations.”
“This is particularly relevant in medical literature, where a negative sentiment in one context—such as describing the progression of a disease—does not necessarily imply a negative evaluation of a treatment or intervention,” the study says. The study stresses the need for additional validation techniques and urges researchers to “be transparent about the limitations in sentiment analysis, and interpret results within the larger context of literature instead of treating sentiment scores like definitive indicators of scientific agreement.”
While the new meta-analysis underscores the need for further robust research into how cannabis might be used to treat cancer symptoms or the disease itself, authors wrote, its “examination of the correlations between cannabis use and large-scale research sentiments, particularly in oncology…lays the groundwork for future research and policy decisions that could significantly impact public health and patient care.”
In a separate, February-published study, people who have cancer and use cannabis report “significant improvement in cancer symptoms.” It also stated that high marijuana prices can burden less-financially stable patients, and “raise questions about the affordability and accessibility of this therapy.”
The National Cancer Institute (NCI) late last year estimated that between about 20 percent and 40 percent of people being treated for cancer are using cannabis products to manage side effects from the condition and associated treatment.
According to the agency, “the growing popularity of marijuana products among cancer patients has been correlated with the number of states who have legalized medical cannabis use.” But research is still lagging on which cannabis products will be effective in treating cancer-related symptoms, and side-effects of treatment.
The research that was referenced by the NCI included a number of reports from the JNCI Monographs journal. That package of 14 articles detailed the results of broad, federally funded cannabis surveys of cancer patients from a dozen agency-designated cancer centers across the country—including in areas where marijuana is legal, permitted only for medical purposes or still outlawed.
A total of just over a third (32.9%) reported cannabis use. Patients said they used it primarily for cancer and treatment related symptoms, including difficulty sleeping, chronic pain and mood fluctuations. Report: The report states that the most popular perceived benefits are “pain, sleep, anxiety, stress, and side effects of treatment.”
Separately, another recent study, in the journal Discover Oncology, concluded that a variety of cannabinoids—including delta-9 THC, CBD and cannabigerol (CBG)—”show promising potential as anticancer agents through various mechanisms,” for example by limiting the growth and spread of tumors. The authors acknowledged, though, that there are still obstacles in the way of incorporating cannabis as a cancer treatment, including regulatory hurdles and the need for optimal dosage.
Other recent research on the possible therapeutic value of lesser-known compounds in cannabis found that a number of minor cannabinoids may have anticancer effects on blood cancer that warrant further study.
While cannabis is widely used to treat certain symptoms of cancer and some side-effects of cancer treatment, there’s long been interest in the possible effects of cannabinoids on cancer itself.
A review of literature from 2019 found that the majority of studies were based on experiments in vitro, which means they didn’t involve humans but instead isolated cancer cells of human origin. Some of the research involved mice. Consistent with the latest findings, that study found cannabis showed potential in slowing the growth of cancer cells and even killing cancer cells in certain cases.
A separate study found that some cases, different types of cancer cells affecting the same part of the body appeared to respond differently to various cannabis extracts.
A scientific review of CBD last year also touched on “the diverse anticancer properties of cannabinoids” that the authors said present “promising opportunities for future therapeutic interventions in cancer treatment.”
Research from 2023 also found that marijuana use was associated with improved cognition and reduced pain among cancer patients and people receiving chemotherapy
The University of Colorado study found that while cannabis can produce intoxicating effects and the initial “high”, it may temporarily impair cognition. However, after using marijuana products purchased from licensed state dispensaries for two weeks, users began to report clearer thoughts.
In 2023, the National Institutes of Health awarded $3.2 million in research funds to researchers to examine whether marijuana access can help reduce health disparities.
The political choice of President Donald Trump to be the White House’s next drug czar, has described medical marijuana as a “fantastic treatment” for patients with serious illnesses and stated that she does not have any “problems” with its legalization even though she may disagree with it personally.
The Trump Administration has also mandated that researchers and staff at the National Cancer Institute must first clear “marijuana”, one of the nearly twenty “controversial” or “high-profile” topics, with their superiors.
The leaked agency document included marijuana and opioids along with other items such as vaccines and COVID-19. It also listed fluoride and measles. Other issues include autism, diversity and gender ideologies and abortion.
NCI is a part of National Institutes of Health, which is itself a part of Health and Human Services.
Prior to publishing anything on the specified topics, NCI staff are required to send the materials to an agency clearance team, says the new memo, first reported by ProPublica.
Staff are advised that depending on the content of the material, it may require additional clearance and review by the NCI directors and deputy directors as well as the NIH or HHS. In some cases the materials will only need to be reviewed once, however the NCI Clearance Team may share them with NCI leadership and/or NIH for their knowledge.
According to a study, an ointment containing the marijuana components CBD and CBG can effectively treat symptoms of eczema.
Side Pocket Images. Photo by Chris Wallis.