Inclusion Criteria:

- Patients with histologically proven operable invasive breast cancer

- Patients who have completed all primary surgery and chemotherapy (if given), and are
candidates to receive hormonal adjuvant therapy

- Women defined as post-menopausal

Exclusion Criteria:

- Patients in whom there is any clinical evidence of metastatic disease

- Patients who, for whatever reason (e.g. confusion, infirmity, alcoholism), are
unlikely to comply with trial requirements

- Patients whose chemotherapy was started more than 8 weeks (ie 56 days) after
completion of primary surgery or whose chemotherapy was completed more than 8 weeks
(ie 56 days) before starting randomised treatment