Several studies have linked estrogens to increased risk of some forms of cancer. This does not mean that estrogens cause cancer, but simply that women using estrogen therapy tend to have a higher than expected rate of cancer development that cannot be explained by other factors.
Breast cancer is probably the most feared condition linked with estrogen therapy. However, like all cancers, it is a multifactorial disease, meaning that it arises from multiple conditions that interact in complex ways. Risk factors now believed to predispose a woman to breast cancer include lifestyle choices (obesity and pregnancy, for example), environmental exposures (such as chemicals or medications), and family history.
As women age, the risk for all cancers, including breast cancer, increases. Scientists have recently discovered that cancer is not simply caused by malignant cells that rage out of control, but also seems to require the failure of the body's own mechanism for killing off damaged cells.
In grossly simplified terms, high levels of estradiol in the blood can lead to increased cell growth, whereas higher levels of progesterone often cause more cell death to occur. Many studies have shown that unopposed estrogens (i.e., estrogens without progesterone) can lead to uncontrolled breast cell growth, which in some cases may trigger cancer. Moderating the risk of developing either breast cancer is possible by balancing the use of estrogens with the appropriate amount of progesterone.
Other risk factors are simply related to natural occurrences that increase your body’s exposure to more estrogen like early menarche or late menopause. The earlier a woman starts menstruating the more exposure, and the same is true with going into menopause later. Nulliparity which is never having been pregnant and a woman having her first pregnancy after the age of 30 are two other natural exposure conditions.
Women who use birth control pills and some types of hormone replacement and women who are considered obese can also have over exposure to estrogen. And other conditions such as a Vitamin D deficiency and an Iodine deficiency may contribute to an imbalance of estrogen.
Not All Estrogens are Created Equal
There are three estrogens found in the human body.
- Estrone also known as E1
- Estradiol also known as E2 the most active form of estrogen
- Estriol which is E3 and also known as the good estrogen
All three estrogens have a role to play in the human hormonal system. The exposure issues arise when the three estrogens are out of balance. This imbalance can happen anytime, but women become very aware of it as they move into menopause when estrogen levels begin to decline.
The Estrogen Quotient
EQ = E3/(E1 + E2) Her estrogen quotient is something every woman should be aware of.
- The lower the Estrogen Quotient, the higher the risk of breast cancer.
- EQ <1.0 : higher risk - this means there is more E1 and E2 and less E3
- EQ >1.5 : lower risk - this means there is plenty of E3 to counteract any E1 or E2 in the body
The Good Estrogen and Breast Cancer
In the 1960’s and 70’s Dr. Henry Lemon found that women who developed breast cancer had a significantly reduced level of one type of estrogen called estriol(E3). He also found that rats that were treated with E3 prior to radiation and chemical exposure had a reduction in the development of mammary cancers. Since then research has shown that E3 almost exclusively acts as an anti-cancer estrogen. Estriol (E3), the good estrogen is critical to reducing breast cancer risk. Women need to have their estrogen quotient tested, because Bio-Identical Hormone Replacement Therapy is available to make sure the estrogens are balanced.
Prevention with Progesterone
Another hormone that has proven to be a protector against breast cancer is progesterone. We all produce this critical hormone, but as estrogen levels fall 40% during menopause, progesterone levels fall by as much as 90%!
What Does Progesterone Do
First and foremost, progesterone opposes the effects of estrogen in breast tissue. There will always be estrone and estradiol in our endocrine system. The presence of progesterone, again at a balanced level, keeps that estrogen from feeding cancer cells and fibrocystic growth in the breast tissue by promoting normal cell death (apoptosis).
Progesterone itself has become regarded as a wonder hormone, good for all kinds of healthy cell growth, but that is a topic for another article. When the estrogen quotient is being tested, progesterone levels should also be part of the criteria of good cancer fighting hormonal health. Low progesterone levels can easily be supplemented.
Can I use hormones?
Women with a history of breast cancer are most often told to avoid all hormones, and yet they are the ones who can benefit the most from using the right hormone replacement. Very accurate hormone testing allows us to create precise levels of the good estrogen and progesterone to promote good breast health for life.