how estrogen cause cancer
Estrogen-only HRT increases the risk of breast cancer, but only when used for more than 10 years. Estrogen-only HRT also can increase the risk of ovarian cancer.The higher breast cancer risk from using HRT is the same for so-called bioidentical and natural hormones as it is for synthetic hormones. Bioidentical means the hormones in the product are identical to the hormones your body produces.strogen-only HRT increases the risk of breast cancer, but only when used for more than 10 years. Estrogen-only HRT also can increase the risk of ovarian cancer.