Inclusion Criteria:

- Postmenopausal females, defined as one from the next :

1. Natural menopause ≥1 year,

2. Surgical ovariectomy,

3. Chemotherapy-induced amenorrhoea ≥ 2 years.

- Patients who have had surgical treatment for histologically confirmed breast cancer
that was non-metastatic at the time of the initial diagnosis.

- Patients who are disease-free after 2 to 3 years of adjuvant tamoxifen treatment.

- Patients whose tumour was estrogen receptor positive (ER+).

- Evidence of a personally signed and dated informed consent document indicating that
the subject (or a legally acceptable representative) has been informed of all
pertinent aspects of the study.

Exclusion Criteria:

- Patients for whom Aromasin® treatment is contraindicated (see SmPC).

- Metastatic breast cancer or a contra lateral tumour.

- Other concomitant adjuvant endocrine therapy.

- Other concomitant antineoplastic treatment.

- Participation in a clinical trial with an investigational drug during the 30 days
prior to enrolment in the study.