“Background: Breast cancer is one of the most prevalent cancers worldwide, posing significant challenges due to its heterogeneity and the emergence of drug resistance. Cannabidiol (CBD), a non-psychoactive compound derived from Cannabis sativa, has recently gained attention for its potential therapeutic effects in breast cancer.

Objective: This review aims to evaluate the antitumor effects of CBD in breast cancer treatment by synthesizing preclinical and clinical evidence, elucidating its mechanisms of action, and exploring its translational potential.

Methods: A systematic review was conducted following PRISMA guidelines. A comprehensive search was performed across PubMed, Google Scholar, Web of Science, and Scopus databases, using keywords such as “Cannabidiol,” “CBD,” “Breast Cancer,” “Therapeutic Agent,” and “Antitumor Effects.” A total of 1,191 articles were initially identified. After duplicate removal and eligibility screening, 34 studies published between 1998 and 2025 were selected, including in vitro, in vivo, and clinical investigations. Studies were assessed based on PRISMA recommendations, considering inclusion criteria such as CBD’s impact on apoptosis, cell proliferation, tumor progression, and molecular mechanisms.

Results: CBD demonstrated significant anticancer effects, including induction of apoptosis, inhibition of cell proliferation, suppression of metastasis, and modulation of the tumor microenvironment. Mechanistically, CBD modulates key pathways such as PI3K/Akt, mTOR, and PPARγ and interacts with CB1, CB2, and non-cannabinoid receptors. Preclinical studies showed CBD’s efficacy, particularly in triple-negative breast cancer (TNBC), while limited clinical trials highlighted its potential as an adjunct to conventional therapies.

Conclusion: CBD offers a promising therapeutic approach for breast cancer, especially for aggressive subtypes like TNBC. However, challenges such as variability in study design, lack of standardized protocols, and limited clinical validation hinder its clinical application. Future research should focus on conducting robust clinical trials, identifying predictive biomarkers, and optimizing combinatorial therapies to integrate CBD into personalized cancer treatment strategies.”

https://pubmed.ncbi.nlm.nih.gov/40275168/

“CBD holds significant promise as a complementary or standalone therapeutic agent in breast cancer treatment, particularly in TNBC, where conventional options are limited. However, clinical validation through well-designed trials, biomarker identification, and safety profiling remains imperative before widespread clinical adoption. Future studies should focus on optimizing combinatorial therapies, investigating long-term effects, and refining pharmacological formulations to bridge the gap between preclinical findings and clinical application. By addressing these challenges, CBD could potentially redefine breast cancer management strategies, offering a safer, more effective, and targeted approach to treatment.”

https://bmccancer.biomedcentral.com/articles/10.1186/s12885-025-14175-z

“Background: High dose chemotherapy is one of the therapeutic strategies for breast cancer and doxorubicin (DOX) as a chemotherapy agent is widely used. DOX indication is limited due to its dose-depended cardiotoxicity. Recently, cannabidiol (CBD) shows antitumoral and cardioprotective effects, so we hypothesized that CBD administration with high-dose DOX chemotherapy can improve anticancer activity and reduce cardiotoxic side effects.

Method: Mice breast cancer model established by injecting 4T1 cell lines. One group was not injected by 4T1 cells as a not cancerous group and received normal saline (NS, 0.1 mL). In cancerous groups, first group was considered as cancerous control and received NS (0.1 mL); the second group received CBD (5 mg/kg, IP) on Days 1,7, and 14; in the third group DOX (5 mg/kg, IV) as CBD schedule was administrated; the fourth group treated with CBD 1 day before DOX injection as pretreatment, and the last group was treated with CBD and DOX at same time with previous doses and schedules. On Day 21, all mice were sacrificed, heart and lungs tissues were obtained and histological sections were isolated. SOD2, iNOS, MMP2, MMP9 were evaluated through western blot and TUNEL test preformed for breast tumor.

Results: Tumor size and weight significantly decreased in DOX, pretreatment CBD + DOX and CBD + DOX groups. Administration of CBD with DOX could not prevent weight loss. TUNEL test demonstrated the highest tumor cell apoptosis in pretreatment CBD + DOX and CBD + DOX. In lungs belonged to CBD + DOX, there was not any sign of metastasis. Cardiac histopathological examination of pretreatment CBD + DOX and CBD + DOX did not show any sign of congestion or inflammation. In CBD + DOX SOD2 increased, also iNOS, MMP2, and MMP9 decreased compared to DOX.

Conclusions: This study demonstrated that simultaneous administration of CBD and DOX can increase antitumoral effect and reduce DOX cardiotoxicity. Nevertheless, CBD can induce cardiotoxicity as administrated alone.”

https://pubmed.ncbi.nlm.nih.gov/39503169/

“This study demonstrated the potent efficacy of cannabidiol in mouse breast cancer model with high-dose chemotherapy on the antitumor, anti-metastasis and cardioprotective roles against doxorubicin. Simultaneous administration of cannabidiol with high-dose doxorubicin not only improved the antitumor and anti-metastasis efficacy, but also could reduce cardiotoxicity by decreasing MMP2 and MMP9 and improving cardiac function by decreasing iNOS. Furthermore, cannabidiol could improve antioxidant system by increasing SOD2. Eventually, these findings demonstrated cannabidiol as a potential effective agent in coadministration with doxorubicin at the same time in improving anticancer effects and reducing cardiotoxicity.”

https://onlinelibrary.wiley.com/doi/10.1002/cam4.70395

“Background: Breast cancer therapy has been facing remarkable changes. Classic treatments are now combined with other therapies to improve efficacy and surpass resistance. Indeed, the emergence of resistance demands the development of novel therapeutic approaches. Due to key estrogen signaling, estrogen receptor-positive (ER⁺) breast cancer treatment has always been focused on aromatase inhibition and ER modulation. Lately, the effects of phytocannabinoids, mainly Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD), have been evaluated in different cancers, including breast. However, Cannabis sativa contains more than 120 phytocannabinoids less researched and understood.

Methods: Here, we evaluated, both in silico and in vitro, the ability of 129 phytocannabinoids to modulate important molecular targets in ER⁺ breast cancer: aromatase, ER, and androgen receptor (AR).

Results: In silico results suggested that some cannabinoids may inhibit aromatase and act as ERα antagonists. Nine selected cannabinoids showed, in vitro, potential to act either as ER antagonists with inverse agonist properties, or as ER agonists. Moreover, these cannabinoids were considered as weak aromatase inhibitors and AR antagonists with inverse agonist action.

Conclusions: Overall, we present, for the first time, a comprehensive analysis of the actions of the phytocannabinoids in targets of ER⁺ breast tumors, pointing out their therapeutic potential in cancer and in other diseases.”

https://pubmed.ncbi.nlm.nih.gov/39338407/

“From the best of our knowledge, this is the first study exploring the molecular targets of minor cannabinoids and, together with previous studies, it reinforces the importance and therapeutic potential of cannabinoids in breast cancer, paving the way for novel and alternative therapeutic approaches and highlighting the medicinal potential of Cannabis.”

https://www.mdpi.com/1424-8247/17/9/1245

“The treatment of patients with triple negative breast cancer (TNBC) relies on cytotoxic therapy. Currently, atezolizumab and chemotherapy can be combined in patients with TNBC. However, this approach is not effective for all patients with low reactivity to atezolizumab. As there is a lack of alternative treatment options, new anti-cancer drugs are urgently needed to enhance atezolizumab reactivity against TNBC. Recent strategies have focused on regulating the expression of programmed death-ligand 1 (PD-L1) or enhancing immune response activation by combining anti-cancer drugs with immune checkpoint inhibitors (ICIs).

Cannabidiol (CBD), a cannabinoid component derived from the cannabis plant, has been reported to have anti-cancer therapeutic potential because of its capacity to induce apoptotic cell death in tumor cells while avoiding cytotoxicity in normal cells.

Previous studies have demonstrated the effects of CBD on apoptosis in various cancer cell types. However, the potential role of CBD as an immune modulator in the regulation of PD-L1 expression and anti-cancer immune responses remains to be explored.

In this study, we found that CBD stimulated PD-L1 expression in TNBC cells, which significantly induced the CBD-mediated cGAS-STING pathway activation. Taken together, we demonstrated that the combination of CBD and anti-PD-L1 antibody enhances the anti-cancer immune response in vitro and in vivo experiments.

Our findings identified the mechanism of PD-L1 regulation by CBD in TNBC cells and suggested that CBD could be a potential candidate for the development of new combinatorial strategies with ICIs in TNBC patients.”

https://pubmed.ncbi.nlm.nih.gov/39226389/

https://aacrjournals.org/cancerimmunolres/article/doi/10.1158/2326-6066.CIR-23-0902/747763/Cannabidiol-enhances-Atezolizumab-efficacy-by