Components of marijuana show “consistent and statistically significant anti-tumor effects” in certain types of cancer, including glioblastoma and breast cancer, according to a new scientific review that also found cannabinoids seem to “enhance chemotherapy efficacy.”
The research, published in the journal Pharmaceuticals, involved a systematic meta-analysis of preclinical trial data investigating the relationship between cannabinoid therapies and multiple cancer types.
Researchers at Semmelweis University and the University of Pécs said their work “provides the most comprehensive systematic synthesis to date of preclinical evidence regarding the antitumor effects of cannabinoids across a wide spectrum of cancer models.”
The review determined that cannabis compounds “show promise as adjuncts in oncotherapy, particularly in glioblastoma and breast cancer, to enhance chemotherapy efficacy.”
“Cannabinoids demonstrated consistent and statistically significant antitumor effects in glioblastoma and breast cancer models,” the study authors said, noting that there’s “additional supportive evidence in lung and prostate cancer.”
“Glioblastoma emerged as the tumor type with the most reproducible evidence base,” the study said.
“Cannabinoids show emerging potential as adjuncts in oncological treatment, with relatively consistent signals observed particularly in glioblastoma and breast cancer models.”
Of the cannabinoids included in the analysis, non-intoxicating CBD “demonstrated the broadest and most favorable profile, with consistent antitumor activity and the advantage of a well-documented safety record in clinical use.”
A study of animal glioblastoma models proved the most compelling, with data showing that subjects receiving cannabinoid therapy saw reduced tumor volume by an average of −980.58 mm³ compared with the control group.
For the breast cancer model, cannabinoids were associated with reduced tumor volume of −402.64 mm³ on average. When combined with the chemotherapy medication doxorubicin, the average tumor volume decrease was −1295.19 mm³ compared with doxorubicin on its own.
Still, the researchers stressed that “not all combinations are beneficial and that rigorous preclinical screening is required before clinical translation,” and unlike CBD, “THC produced highly variable effects” so the therapy’s benefits may not be “universal.”
This represents one of the latest pieces of scientific literature examining the therapeutic potential of cannabinoids in cancer treatment.
For example, another recent systemic review concluded that studies “consistently show” that the CBD is a potential “anticancer agent across different cancer types”—and that effect applies to dogs as well as humans.
A similar analysis showed that CBD “holds substantial promise as an anti-tumor agent” in addition to its other anti-inflammatory properties.
Scientists explored CBD’s effect on many types of cancer—including some of the most aggressive ones, such as glioblastoma, which affects the brain. They also noted it can help suppressing the growth and metastasis of other cancers, including breast, lung, colorectal, ovarian and prostate, among others.
In 2025, a paper published in the journal Pharmacology & Therapeutics, assessed a range of clinical and preclinical findings that the efficacy of chemotherapy drugs can be enhanced by medical marijuana.
In a sign of greater acceptance of medical applications of cannabis, President Donald Trump’s choice to serve as the next White House drug czar has called medical marijuana a “fantastic” treatment option for seriously ill patients and said she doesn’t object to legalization, even if she might not personally agree with the policy.
Also last year, a study found that “patients with cancer using cannabis report significant improvements in cancer-related symptoms.”
