APOLLO(Aromatase inhibitor Patient cOmpLiance program with qoL questionaire) - APOLLO

Inclusion Criteria

• - Provision of written informed consent
• - Patients with early breast cancer who are scheduled to receive first-line adjuvant endocrine therapy with aromatase inhibitor under the routine clinical practice
• - Histologically or cytologically proven to be HR+(ER or PR +)
• - Postmenopausal woman, defined as a woman fulfilling any of the following criteria(by the local guideline):
• * Age >= 50 years
• * Age < 50 years with amenorrhoea > 12 months and an intact uterus
• * FSH levels within postmenopausal range (over 30-40 IU/ml), or
• * Having undergone a bilateral oophorectomy.
• * No other concomitant endocrine therapy such as estrogen therapy or selective estrogen receptor modulators