Effect of Aromatase Inhibitors on Breast Magnetic Resonance Imaging (MRI)

Phase II Study of the Effect of Acute Aromatase Inhibition on Breast MRI Postmenopausal Women

This study is a primary investigation to determine the usefulness and safety of a short course of a relatively high dose of letrozole (a medication used to decrease the female hormone estrogen which is produced locally inside the breast after menopause) in improving the performance of of breast MRI (Magnetic Resonance Imaging). The inhibition of estrogen in the breast by letrozole might help better identifying of suspicious areas in the breast and could assist radiologists in distinguishing between benign breast areas and cancer tissue. This might help reducing the rate of call backs and unnecessary biopsies for patients. We expect to enroll 20 healthy postmenopausal women in this study.

A breast MRI will be performed in the standard way for diagnosis and to serve as a baseline. A second MRI will be performed within a month and following administration of letrozole 12.5 mg daily for three days to reduce breast estrogen levels and in anticipation of lowering breast gadolinium dye uptake.

Inclusion Criteria:

• Women are eligible to participate if they are 40 years or older and have been menopausal (had no menstrual bleeding during the past 12 months)

Exclusion Criteria:

• History of bilateral mastectomy, osteoporosis or renal impairment.