It is prescribed in case of breast cancer in postmenopause woman.
Studies show that women with higher blood levels of estrogen have breast cancer more often. And the estrogen receptor (ER) is expressed in approximately 75% of breast cancers. In the case of postmenopausal women, as estrogens promote the accumulation of subcutaneous fat while visceral fat varies inversely with levels of estrogens. Consequently, the loss of endogenous estrogen production with menopause is associated with an increased risk to develop visceral obesity. That's why estrogen receptor agonist binds the estrogen receptor on the fat cell and blocks the metabolic processes inside the fat cell. That's why women taking fulvestrant 500 mg injection become so slim in appearance while still on the injection.