Letrozole in Post-Menopausal Patients with Operable Hormone-Sensitive Breast Cancer

Patients will receive a prescription for letrozole to be taken orally for 7-30 days to allow for variations in surgical scheduling. Patients are to undergo surgical resection of their tumor the day after the last dose of letrozole. Post-treatment tumor biopsies (a goal of 4-6 cores) will be obtained following 7-56 days of letrozole treatment on the day of surgery.