Preoperative Fulvestrant With or Without Enzalutamide in ER+/Her2- Breast Cancer

This is a randomized two arm phase II study to further evaluate the efficacy of fulvestrant plus enza compared to single agent fulvestrant in postmenopausal women with locally advanced AR+/ER+/Her2- BC who will have local surgery after \~4 months on treatment. After consent, all patients will get a tissue biopsy, and than half the patients will get fulvestrant alone (standard dosing) and the other half of the patients will get fulvestrant plus enzalutamide. At \~4 weeks, a biopsy will be done and therapy will be continued. Hormone therapy will continue for \~4 months at which point the patients will undergo surgical resection.