Estrogen and Cancer — What You Need to Know

Photo: Our grateful thanks to William Farlow Leva on Unsplash!


by Connie Hernandez, ND

While there are breast cancers that aren’t estrogen receptor positive (ER+), most breast cancer does grow under the influence of estrogen. 

Breast cancer patients are well aware of this, and after surgery and/or radiation, and/or chemotherapy, most are instructed to take five years’ of either Tamoxifen (which inhibits the transcription of estrogen responsive genes), or an aromatase inhibitor which blocks the conversion of androgens into estrogens.

Although these medications are effective at reducing estrogen levels in breast cancer patients, there’s more to the estrogen story.

Dr. Connie Hernandez, ND

First of all, estrogen plays a part in driving many cancers – not just breast cancer. For example, the role of hormones in endometrial cancer, ovarian cancer, prostate cancer, and colorectal cancer is well known, and increasing evidence points to an estrogenic influence in melanoma.

Second, if estrogen were the cause of breast cancer, it would seem that young women would have the highest breast cancer risk – not older women who have much lower levels of estrogen.

It’s important to understand that estrogen is not a single biochemical entity, but a group of similar estrogenic molecules.

Estradiol (E2) is the primary premenopausal estrogen.

Estrone (E1) is the primary postmenopausal estrogen.

E1 and E2 are both quite powerful and convert back and forth into each other. They are then metabolized through various processes into a number of metabolites, some of which are inflammatory and pro-carcinogenic, and some of which are protective.

Estriol (E3) is at the end of the metabolic chain. E3 is a weak estrogen that doesn’t convert back to the other estrogens.

E3 is considered anti-carcinogenic and potentially of use in autoimmunity. A high ratio of E3 to E1+E2 has been found to be protective against estrogenic cancers, and confers a more favorable prognosis in breast cancer patients.

It remains a mystery to me that conventional oncology considers only the total estrogen and doesn’t consider estrogen metabolism and metabolites.

Familial and individual patient histories of estrogenic conditions, including various male and female cancers, uterine fibroids and endometriosis, clue us into issues with estrogen metabolism.

At Pacific Naturopathic, we use urinary steroid testing to reveal current issues with the processes that govern estrogen metabolism. Knowing what these issues are, we can address them in order to positively affect estrogen metabolism while addressing current issues and reducing the risk of future problems 

Delving into estrogen metabolism another way, we can look at variations in the genes that code for estrogen metabolism. This genetic variability is relevant to any estrogen-influenced cancer, as well as to other processes of detoxification. 

Happily, the field of nutrigenomics has shown that these genetic predispositions may or may not manifest, and offers information on what factors turn various genes on or off.

  • For example, ground flax seed can move E1 and E2 toward E3.
  • Broccoli constituents can affect conversion to toxic metabolites of E1.
  • B6, B12, and folate, among other nutrients, can positively affect methylation, another process that detoxifies estrogen.

A number of other nutritional and botanical medicines, in addition to lifestyle modification, can positively impact the disease process in both cancer and many other conditions influenced by estrogen.

Though decreasing estrogen levels plays a part when existing cancers are driven by estrogen, at Pacific Naturopathic we find it wise to delve a bit deeper for optimal results.

This is particularly important in individuals with a family history of estrogenic issues, because understanding and addressing modifiable genetic factors may prevent the expression of those genes.

For information about the services we offer at Pacific Naturopathic, please give us a call at 650-961-1660, or use the convenient Contact Form to get in touch, or follow the link to: Consultations – Pacific Naturopathic. Thank you!