This article is critical for women with breast cancer to read, especially if you have estrogen dominant breast cancer, which accounts for about 70% of all breast cancers diagnosed. This article will explain why, in my opinion, all women with breast cancer should have their estrogen levels tested, and why you should also have a stool test. Let’s get into the nitty-gritty!
Recent Government of Canada stats tells us that 1 in 8 women will be diagnosed with breast cancer in their lifetime. Breast cancer accounts for 26% of ALL NEW cases yearly, which is absolutely staggering. As previously mentioned, estrogen positive cancer is the most common type of cancer that women have.
If you have estrogen positive breast cancer, you will most commonly be prescribed a drug called Tamoxifen, or Letrozole/Anastrozole. These drugs work to lower estrogen in the body, so that it cannot continue to stimulate cancer cells and cause them to spread or grow.
However, once you start taking these drugs, how do you know they are working? It is not standard practice that estrogen levels are tested in the blood, and it is my argument that all women should have their estrogen tested.
Why You Should Have Your Estrogen Levels Tested
A 2009 study recruited women who had been diagnosed with breast cancer and who were also taking an estrogen blocker. Their aim of the study was to actually measure estrogen levels in the blood, so see how much estrogen was lowered. While they found that many women did in fact have lowered estrogen levels, they also found that a significant proportion of women did not. In fact, they actually found that some women had higher estrogen levels than they had before starting the drug. They called this rebound estrogen.
Since then, several more recent studies have also confirmed this finding. A 2016 study tested estrogen levels in women taking Tamoxifen and found that 17% of women had estrogen values that were deemed to be above desirable levels (J Clin Oncol, 2016; 34(14)). A 2017 study did the same test in women taking Letrozole, and also found that a significant proportion of women did not have lowered estrogen (Breast Cancer Res Treat, 2017; 161(3)). And again in a study looking at the drug Anastrozole; estrogen levels were not decreasing to what was expected (Steroids, 2015:99).
This is very concerning because this means that the drugs you are taking to prevent cancer from recurring may not actually be working.
Why You Should Do a Comprehensive Stool Analysis
Have you heard of the microbiome? This term is all the rage these days. It refers to the entirety of the gut microbes that live in our body, and also all of the genes that these microbes carry. These bacteria and their genes are the subject of intense focus lately, and researchers are finding that they directly impact our health, and can contribute to heart disease, autoimmune diseases and even cancer.
Let’s go back to estrogen for a second. When our ovaries or other organs produce estrogen, it gets detoxified by the liver, and then a large amount of that detoxified estrogen gets sent to the gut where it ideally leaves our body via our bowel movements. But researchers have shown that there are a number of different types of bacteria that can actually re-activate that estrogen, and that estrogen can then go back into our blood stream where it has the potential to stimulate breast cancer cells again.
A comprehensive stool analysis can test for the types of bacteria that we know can re-activate estrogen back into our body. This is absolutely critical for a women with estrogen positive breast cancer, because for some women, the estrogen blocking drugs they are taking will not work on this type of re-activated estrogen.
If you have estrogen positive breast cancer, it is highly recommended you test your estrogen levels, and see what kind of bacteria you have living in your gut. Estrogen blocking drugs are an important part of cancer prevention, but it may not be wise to rely entirely on these medications alone. This type of testing is what is called personalized medicine – it’s the future medicine, at your fingertips today!