breast cancer

For cancer, there are no favorites. It doesn't matter the color of your skin, whether you're young or old, rich or poor. When the diagnosis arrives, as it might for half of us in our lives, we put our hopes in accessing the best treatment to maximize our chances of survival.

And what is Cancer?

Cancer is an uncontrolled and excessive growth of our cells. This uncontrolled growth can occur in different organs or tissues of our body due to mutations at the genetic level, caused by radiation poisoning, among others.
In this particular case we will focus on breast cancer, so that this condition affects cells located in the mammary glands, and is one of the causes of high mortality worldwide, being ductal carcinoma the most common among them. From the moment the modifications in the cells begin until the tumour becomes palpable, many years are required to pass. It is estimated that one in eight women will develop breast cancer. Breast cancer is difficult to treat because there are few biomarkers that indicate when someone has the disease, and many patients show or develop resistance to current therapies. In addition, several specific types of breast cancer respond poorly to modern treatments. These difficulties underscore the importance of exploring new treatments for breast cancer.
Although breast cancer is a typically female disease, it can also occur in men, however in a much smaller percentage, accounting for less than 1% of tumors in men. Within the Spanish context, the study led by the Spanish Association Against Cancer, reported in 2014 an incidence of 25,000 cases of breast cancer, translating into a 29% of tumors that affect women between 35 and 80 years (1).

How can the use of cannabinoids help?

Medical cannabis can help patients tolerate conventional cancer treatments, such as chemotherapy and radiation, and can be used in conjunction with these treatments with a low likelihood of interaction with other drugs. This means that there is rarely a reason to avoid combining cannabis with conventional cancer treatments. Along with symptom relief and improvement of quality of life for cancer patients, cannabinoids have also shown anti-cancer effects in many experimental cellular and animal models. And a large body of anecdotal evidence suggests that human cancers also respond to treatment with cannabinoids. Several patients have experienced decreased or stopped tumor growth, and others have experienced complete remission from aggressive cancers when using cannabinoid extracts.

CBD and cancer

Scientists at the University of Western New England in Springfield, Massachusetts, briefly reviewed 10 studies that shed light on how CBD might interact with cancer treatments. Half of these studies examine how CBD can affect the metabolism and distribution of cancer drugs.
As the authors describe, large doses or regular use of CBD can both increase and decrease the levels of different drug metabolizing enzymes, called CYP, that will alter the effectiveness of a drug. At even higher doses, CBD can also modify the expression of certain proteins produced by cancers to resist chemotherapy (2).

CBD and breast cancer

Cannabidiol (CBD), one of the main non-psychoactive components of cannabis, is considered an antineoplastic agent because of its in vitro and in vivo activity against tumour cells. However, the exact molecular mechanism by which CBD mediates this activity has not yet been elucidated. In a study conducted by the scientific journal Molecular Cancer Therapeutics, CBD-induced cell death of breast cancer cells has been demonstrated independently of activation of cannabinoid and vallinoid receptors. Electron microscopy revealed morphologies consistent with the coexistence of autophagy and apoptosis (cell death). The analysis confirmed these findings, demonstrating that CBD induces and subsequently inhibits endoplastic reticulum stress (3).
Another study published by the same journal shows that cannabidiol (CBD) may regulate downward the expression of Id-1 in aggressive human breast cancer cells. The concentrations of CBD effective in inhibiting the expression of Id-1 correlated with those used to inhibit the proliferative and invasive phenotype of breast cancer cells. CBD was able to inhibit the expression of Id-1 at the mRNA and protein levels in a concentration-dependent manner. These effects appeared to occur as a result of inhibition of the Id-1 gene at the promoter level. Importantly, CBD did not inhibit the invasiveness of cells ectopically expressing Id-1.
In conclusion, CBD represents the first non-toxic exogenous agent that can significantly decrease the expression of Id-1 in metastatic breast cancer cells, leading to down-regulation of tumor aggressiveness (4).
Scientists have also demonstrated efficacy data with CBD in preclinical breast cancer models. In a study published by de Breast Cancer Research and Treatment, the results demonstrate the potential to lead to the development of new non-toxic compounds
for the treatment of breast cancer metastasis, and the information obtained from these experiments broadens our knowledge of both the biology of cannabinoids as it relates to cancer progression (5).

Final conclusions

Any medical treatment carries certain risks, but high-dose cannabis is not lethal and is much safer than conventional chemotherapy, although the effectiveness of high-dose cannabis for cancer has not been studied in great depth. However, studies
presented in this article highlight the value of continued research into the potential use of CBD as an antineoplastic agent (substances that prevent the development, growth, or proliferation of malignant tumor cells).

Thus, before using CBD or any cannabis product to help address cancer-related problems, a physician experienced in the use of cannabis should be consulted for advice.


(1) Breast Cancer [PDF]. (2014). Madrid: Spanish Association Against Cancer.
(2) Opitz, B. J., Ostroff, M. L., & Whitman, A. C. (2019). The Potential Clinical Implications and Importance of Drug Interactions Between Anticancer Agents and Cannabidiol in Patients With Cancer. Journal of Pharmacy Practice, 33(4), 506-512.
(3) Shrivastava, A., Kuzontkoski, P. M., Groopman, J. E., & Prasad, A. (2011). Cannabidiol Induces Programmed Cell Death in Breast Cancer Cells by Coordinating the Cross-talk between Apoptosis and Autophagy. Molecular Cancer Therapeutics, 10(7), 1161-1172. doi:10.1158/1535-7163.mct-10-1100
(4) Mcallister, S. D., Christian, R. T., Horowitz, M. P., Garcia, A., & Desprez, P. (2007). Cannabidiol as a novel inhibitor of Id-1 gene expression in aggressive breast cancer cells. Molecular Cancer Therapeutics, 6(11), 2921-2927. doi:10.1158/1535-7163.mct-07-0371
(5) Mcallister, S. D., Murase, R., Christian, R. T., Lau, D., Zielinski, A. J., Allison, J., Desprez, P. (2010). Pathways mediating the effects of cannabidiol on the reduction of breast cancer cell proliferation, invasion, and metastasis. Breast Cancer Research and Treatment, 129(1), 37-47. doi:10.1007/s10549-010-1177-4

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