Optimal Duration of Pre-operative Treatment With Letrozole and to Correlate Clinical Efficacy With Appropriate Surrogate Markers

Inclusion criteria

• Female Breast Cancer patients with primary invasive breast cancer, histologically confirmed by core needle biopsy, whose tumors are estrogen (ER) and / or progesterone (PgR) positive (Clinical Stage *T2, T3, T4a,b,c, N0, M0)
• Patients after menopause
• Tumor measurable by clinical examination, mammography and ultrasound
• Adequate bone marrow, renal and hepatic function
• A life expectancy of at least 6 months.

Exclusion criteria

• Prior treatment with aromatase inhibitors or antiestrogens.
• Uncontrolled endocrine disorders such as diabetes mellitus, confirmed hypo- or hyperthyroidism, Cushing´s Syndrome, Addison´s disease (treated or untreated), Patients with unstable angina, uncontrolled cardiac disease (e.g. Class II or IV New York Heart Association's Functional Classification).
• Patients with tumors in both breasts, evidence of inflammatory breast cancer or distant metastasis
• Patients who are eligible for breast conserving surgery.
• Concomitant anti-cancer treatments such as chemotherapy, immunotherapy/biological response modifiers (BRM's), endocrine therapy (including steroids), bisphosphonate therapy and radiotherapy. Patients who have received HRT will NOT be excluded, provided that HRT is discontinued at least 2 weeks prior to entry into the study.

Other protocol defined inclusion/exclusion criteria may apply