Estrogen Dominance & Breast Cancer
While a healthy lifestyle and regular screenings are highly important, one of the key principles in breast cancer prevention is hormone balancing. In particular, a woman’s risk can be drastically reduced by identifying and properly treating estrogen dominance —a condition that occurs when a woman’s estrone and progesterone levels are out of balance—which has been proven to cause breast, uterine and ovarian cancers.
Estrogen, the primary female hormone, affects nearly every organ in the body and is actually made up of several family members: estrone, estradiol and estriol. Estrone— which is made in abundance throughout a woman’s life, even during menopause—has the role of stimulating cellular growth in breast and endometrial tissue. In order for these cells to not proliferate and grow endlessly (which is ultimately a cancer cell) they must be regulated to die at a set point. The determined point is 28 days for breast and endometrial tissues, hence the 28-day cycle. This process of programmed cellular death is called apoptosis, and it is regulated by another critical female hormone, progesterone.
This explains why a woman’s risk of breast and uterine cancer is significantly lowered during pregnancy. This is because pregnant women have an abundance of progesterone—referred to as the pregnancy or “pro-gestation” hormone—for 9 months straight, thus protecting these tissues from proliferation.
When estrone and progesterone are in proper balance, the proliferative phase is offset by apoptosis, brought on by a decrease in estrogen and an increase in progesterone at day 14 of a women’s cycle. A woman is known as estrogen dominant, however, when she produces insufficient amounts of progesterone, and thus is unable to offset the cellular growth stimulated by estrone. This allows the breast and endometrial tissue to grow rapidly, unopposed, leading to an increased risk of breast, ovarian and uterine cancer. This risk can be greatly reduced by simply balancing these levels through bioidentical hormone replacement therapy.