Assessment of Quality of Life, Bone Density and Safety in Postmenopausal Breast Cancer Patients With Letrozole Therapy

1. TOI is the sum of the scores from the physical and functional well-being and the breast cancer subscales. 2. To assess incidence of adverse events (including cardiovascular, cerebrovascular, and endocrine, musculoskeletal) in Korean postmenopausal breast cancer patients in early adjuvant setting. 3. To assess the effect of letrozole (Femara) on BMD in early adjuvant setting. 4. To assess the effect of letrozole (Femara) on total cholesterol in early adjuvant setting.