Phase II Study of Neoadjuvant ArOMatase Inhibitor Therapy for ER+ Breast Cancer (NAOMI)

This is a single-arm, open-label study testing the effects of neoadjuvant therapy with the aromatase inhibitor letrozole in post-menopausal women with Stage I-III ER+, HER2- breast cancer. Eligible subjects will be treated with letrozole therapy for 4 to 24 weeks prior to surgical resection of the tumor. Tumor specimens obtained at baseline (diagnostic biopsy) and at surgery (surgical specimen) will be compared using molecular analyses. A subset of subjects will be asked to provide an optional research tumor biopsy prior to treatment for molecular analysis. Subjects will be evaluated for treatment adherence and provide feedback via survey questionnaires to identify potential causes of non-adherence.