Dr. Frankel's Journal

HORMONALLY SENSITIVE BREAST CANCER & THC

July 28, 2017
Allan Frankel, MD

Does THC increase estrogen levels or sensitivity, potentially worsening hormonally sensitive breast cancer?

Hormonally Sensitive Breast Cancer

Copyright: Dusanka Visnjican

Individuals diagnosed with a hormonally sensitive breast cancer will most likely receive some form of estrogen blocker, possibly in conjunction with other therapies or procedures. If they are advised that adding THC to their treatment plan may increase estrogen levels or have estrogen like effects on their cancer, it is perfectly natural to question using cannabis medicines containing THC. This may result in the use of a cannabis medicine containing significantly less THC, which I have found to be a less effective therapy.

I first heard discussions about potential negative effects of THC on hormonally sensitive breast cancer about a year ago. My first reaction was we just didn’t know enough to make a definitive statement. Personally, my research on the subject had not led me to a conclusion I was comfortable with. Thankfully, there is continuing research, and I have continued to do thorough searches of the National Library of Medicine.

I have found several dozen articles on the subject. With the exception of one pretty old article, I found both THC and CBD are shown to reduce estrogen levels and block estrogen effects.

As you will read in the referenced articles below, this is achieved in a number of different ways. THC has effects on estrogen receptors, the pituitary gland and other locations related to estrogen production and levels.

So, the findings indicate THC is not an issue to use with hormonally sensitive breast cancer; in fact, it might actually help.

Below are a few good articles. There are many, many more.

Delta(9)-tetrahydrocannabinol inhibits 17beta-estradiol-induced proliferation and fails to activate androgen and estrogen receptors in MCF7 human breast cancer cells.

Δ(9)-Tetrahydrocannabinol disrupts estrogen-signaling through up-regulation of estrogen receptorβ (ERβ).

Delta(9)-tetrahydrocannabinol inhibits 17beta-estradiol-induced proliferation and fails to activate androgen and estrogen receptors in MCF7 human breast cancer cells.

Antiestrogenic effects of marijuana smoke condensate and cannabinoid compounds.

Evidence for a direct anterior pituitary site of delta-9-tetrahydrocannabinol action.

Specific inhibition of FSH-stimulated cAMP accumulation by delta 9-tetrahydrocannabinol in cultured rat granulosa cells.