The purpose of this study was to give access to postmenopausal women with estrogen sensitive primary breast cancer to exemestane for the adjuvant treatment of breast cancer after the use of tamoxifen and to collect all serious adverse events.

Inclusion Criteria:

• Postmenopausal patients
• Patients with early breast cancer after adequate loco-regional treatment and eventual adjuvant chemotherapy, treated with tamoxifen for 2-3 years OR treated with tamoxifen for 2-3 years and consecutive exemestane treatment, provided the total duration of endocrine treatment is less than 5 years
• Estrogen receptor positive breast cancer patients
• Patients who remain free from disease following treatment with tamoxifen

Exclusion Criteria:

• Patients taking other drugs for the adjuvant treatment of breast cancer
• Patients taking hormone replacement therapy
• Donation of blood or blood products for transfusion during the 30 days prior to initiation of treatment with study drug, at any time during the program or 30 days after completion of treatment