Hormonal therapy for breast cancer: focus on fulvestrant.

Fulvestrant, the first drug of the pure estrogen antagonists to be approved for clinical use, is a new therapeutic option for metastatic breast cancer. Fulvestrant offers a unique metastatic breast cancer treatment option because its mechanism of action is the destruction, rather than the blockade, of estrogen receptors. No known agonistic activity exists, limiting potential side effects and receptor exhaustion. The side effect profile of fulvestrant is related to its antiestrogen effect and includes gastrointestinal disturbance, urinary tract infection, and vaginitis. Suggestions for managing the side effects of fulvestrant are described, and a case study is provided as an illustrative aid in understanding the role of this new hormonal agent.