Feasibility Study of Adjuvant Enzalutamide for the Treatment of Early Stage AR (+) Triple Negative Breast Cancer

The study population for Step 1 must meet the following eligibility criteria: Inclusion Criteria: * Stage 1, 2 or 3 invasive breast cancer which is triple negative. Triple negative breast cancer is defined as ER \<1, PR \<1 and HER2 0 or 1+ or FISH not amplified if IHC 2+. * AR testing may be performed while patient is undergoing other adjuvant therapy (i.e., surgery, chemotherapy, radiation). * Willing and able to provide informed consent. Woman at least 18 years of age. * Patient is a candidate for treatment of their early stage breast cancer. The study population for Step 2 will meet the eligibility criteria: Inclusion Criteria: * Stage 1, 2 or 3 invasive breast cancer which is triple negative. Triple negative breast cancer is defined as ER \<1%, PR \<1% and HER2 0 or 1+ or FISH not amplified if IHC 2+. * AR(+), defined as ≥1% nuclear staining by IHC testing. The assessment of AR expression may have been performed any time in the past and is not limited to participation in Step 1. * Any neoadjuvant or adjuvant chemotherapy regimen is permitted. Prior chemotherapy for the treatment of this breast cancer is not required. * At least 4 weeks from end of surgery, chemotherapy, or radiotherapy with resolution of any toxicity to Grade 1 or less, excluding alopecia. * Patients are eligible to participate within 6 months of completion of therapy for their breast cancer. This includes prior radiation therapy if needed. * ECOG performance status of 0 or 1. * Willing and able to …