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Estrogen Metabolism Test

There is no one test that accurately predicts preset cancer risk, However, several tests are available that may be of interest in breast cancer. For example, saliva hormone testing provides evidence of a common pattern of hormone imbalance in breast cancer patients. Other tests may have predictive value for breast cancer risk, including the tumor marker CA15-3 and Estrogen Metabolism Ratio.

What is the Estrogen Metabolism Ratio (EMR)?

The estrogen metabolism ratio looks at how estrogens are broken down by the body. While estrogen is a good hormone in many cases, helping women develop and support proper menstruation, too much of it can cause problems in the body. Sometimes the estrogen amounts are the lest of my concern since the issue lies in the breakdown products which are very harmful to the body. Two of the metabolites of estrogen are:

  1. 16-alpha-hydroxyesterone (16OHE1)
  2. A more potent estrogen and may promote hormone dependent cancers like breast cancer
  3. Also linked to problems with hormone balance and menstrual issues relating to pain, mood and fluctuating cycles
  1. 2-hydroxyestrone (2OHE1)
  2. protective against breast cancer
  3. supports a health menstrual cycle

EMR (Estrogen Metabolism Ratio) = 2-hydroxyestrogen / 16-hydroxyestrogen

A proper balance between the two metabolites is important in maintaining good health. Determining the ration of 2-hydroxyestrogens to 16-hydroxyestrogens may give an indication of breast cancer risk. Studies suggest that an estrogen metabolism ratio greater than 2.0 is associated with decreased breast cancer risk in both pre-and post-menopausal women.


Several retrospective case-control studies have demonstrated that the EMR is lower in both pre and postmenopausal women diagnosed with breast cancer, compared to disease-free, age-matched controls. A lower EMR is most often associated with decreased urinary excretion of 2OHE1, the principle urinary estrogen metabolite that is protective against breast cancer and supports a healthy menstrual cycle.

Several prospective case-controlled studies have examined the relationship between EMR and future risk of breast cancer. Estrogen metabolism ratios were measured in frozen urine specimens obtained at the inception of a large observational study of women. The findings were as follows:

Postmenopausal Women

After more than 16 years of follow-up, a baseline EMR greater than 2.1 resulted in a 30% decrease in the risk of breast cancer in post-menopausal women compared to those whose EMR was less than 1.4 at baseline.

Premenopausal Women

Again after 16 years of follow up, a baseline EMR greater than 2.4 resulted in a 30% decrease in the risk of breast cancer in pre-menopausal women compared to those whose EMR was less than 1.8 at baseline.

The studies above suggest that maintaining a minimum EMR between 2.0 and 2.4 through premenopause and into postmenopause may modestly reduce the risk of breast cancer.


Although research in this area is preliminary, the EMR may also help identify men at risk for prostate cancer.