High drop-out rate leads to the conclusion: not enough data will be available to perform proper analyses of data collected after follow-up month 24 visit

Approximately 60 specialised clinics and 420 office based gynaecologists or oncologists will participate in this in practice evaluation program (NIS). The clinic and approximately 7 office based physicians will collaborate within their breast centre networks to conduct this program. A breast centre network should be able to recruit in this program approximately 80 patients (approximately 40 patients per year). It is planned to enroll approximately 4674 patients in this NIS (2337 patients per arm). The patient population will include postmenopausal women with hormone-receptor positive primary breast cancer scheduled for upfront adjuvant endocrine treatment with anastrozole according to the current standard medical procedures.

Inclusion Criteria:

• Histological/cytological confirmed primary diagnosis of early breast cancer
• Postmenopausal
• Hormone receptor positive

Exclusion Criteria:

• Patients with severe renal function disorders
• Patients with moderate or severe disorders of hepatic function
• Concomitant treatment with drugs known to affect sex hormonal status and tamoxifen

Postmenopausal women with hormone receptor positive primary breast cancer scheduled for upfront adjuvant endocrine treatment with anastrozole according to the current standard medical practice