Open Label Study of Postmenopausal Women With ER and /or PgR Positive Breast Cancer Treated With Letrozole

Inclusion criteria

• Postmenopausal woman able to comply with the protocol requirements with primary invasive breast cancer, histologically confirmed by core needle biopsy, whose tumors are estrogen (ER) and / or progesterone (PgR) positive, defined by core biopsy immunohistochemistry with > 10% positive malignant epithelial cells.
• Clinical stage *T2, T3, T4a,b,c, N0, 1 or 2, M0

• Clinical stage T2 tumors which in the Investigators opinion would not be eligible for breast-conserving surgery.
• Post menopausal status defined by one of the following:

• No spontaneous menses for at least 1 year, in women > 55 years.
• Spontaneous menses within the past 1 year but amenorrhoeic in women ≤ 55 years (e.g. spontaneous or secondary to hysterectomy), and with postmenopausal gonadotrophin levels (LH y FSH levels > 40 IU/L) or postmenopausal estradiol levels (< 5 ng/dl) or according to the definition of "postmenopausal range" for the laboratory involved.
• Bilateral oophorectomy. (Prior to the diagnosis of breast cancer).
• Tumor measurable by clinical examination, mammography and ultrasound.

Exclusion criteria

• Prior treatment with letrozole or tamoxifen.
• Uncontrolled endocrine disorders such as diabetes mellitus, confirmed hypo- or hyperthyroidism, Cushing's Syndrome, Addison's disease (treated or untreated).
• Patients with unstable, angina, or uncontrolled cardiac disease (e.g. Class III or IV New York Heart association's Functional Classification).
• Patients with bilateral breast tumors
• Patients who are eligible for breast conserving surgery
• Evidence of inflammatory breast cancer or distant metastasis.

Other protocol-defined inclusion/exclusion criteria may apply.