Mammogram Pretreatment With Ulipristal Acetate

PRIMARY OBJECTIVE: I. To evaluate change in percent dense area from antecedent to study screening mammograms. SECONDARY OBJECTIVES: I. To assess for menstrual cycle phase following this regimen of ulipristal acetate (UPA). II. To assess adherence, tolerability and acceptability of the short course of UPA prior to a mammogram. EXPLORATORY OBJECTIVES: I. To determine the presence of radiographic changes in clinical breast density on screening mammograms following a course of UPA. II. To characterize a change in background parenchymal enhancement (BPE) on breast magnetic resonance (MR). III. To describe the effect of the intervention on routine clinical care. IV. To determine the longitudinal effect of the intervention on primary objective (clinical breast density score). OUTLINE: Patients receive ulipristal acetate orally (PO) every 5 days for 4 doses in the absence of unacceptable toxicity (study days 1, 5, 10 and 15). Patients then undergo a mammogram on study day 20. Patients also undergo base magnetic resonance imaging (MRI) and blood sampling which will be repeated on study day 20. After completion of study intervention, patients are followed up at 1-7 days and may be followed up to 24 months for results of subsequent screening mammograms.