Hormone Therapy

For breast cancers that test positive for estrogen or progesterone receptors, hormone therapy is an effective treatment in both early and metastatic disease.  ER+ and PR+ breast cancers rely on a supply of these hormones to fuel their growth.  If that supply is reduced or blocked, the tumor’s ability to grow is limited.  About 80% of breast cancers are ER+ and 65% are both ER+ and PR+. 

For women with early stage breast cancer, hormone therapy can be used as an adjuvant treatment following surgery, sometimes with chemotherapy, to help prevent recurrences.  For women with advanced disease, hormone therapy can slow down or stop the growth of the cancer.  Several very promising studies show that in certain women at high risk for developing breast cancer, hormone therapy can reduce that risk significantly, effectively preventing breast cancer.

There are different types of hormone therapy available: