Statement: Participants of the primary trial cannot be currently receiving treatment for rheumatoid arthritis, experiencing poorly controlled migraines or have any prior history of invasive breast cancer in the last 3 years.
Primary_evidence: Inclusion Criteria:   Post-menopausal women at high risk for development of breast cancer   On a stable dose of hormone replacement therapy   have cytomorphologic evidence of hyperplasia +/- atypia and Ki-67 expression >1.5% in benign breast epithelial cells acquired by RPFNA   Serum level of 25-OH vitamin D of at least 30 ng/ml prior to study entry   Willing to have a repeat random periareolar fine needle aspiration (RPFNA) and mammogram at 6 months and 12 months (if participating in the open label portion of the study) following initiation of study drug Exclusion Criteria:   Prior history of osteoporosis or osteoporotic fracture.   Prior history of invasive breast cancer or other invasive cancer within five years from date of study entry.   Current and chronic use of cyclooxygenase-2 (COX-2) specific inhibitors or NSAIDs   Receiving treatment for rheumatoid arthritis or fibromyalgia   Current history of poorly controlled migraines or perimenopausal symptoms   Currently receiving other investigational agents.   Receipt of more than 6 months of an aromatase inhibitor (anastrozole, exemestane, letrozole, etc.) at any time in the past.