To describe patients' compliance of taking Aromatase Inhibitor as an adjuvant treatment in the postmenopausal, early breast cancer as seen under current practice

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

Exclusion Criteria:

• Recurrence of breast cancer
• Known hypersensitivity to aromatase inhibitor or to any of the excipients
• Any severe concomitant condition which makes it undesirable for the patient to participate in the trial or which would jeopardize compliance with the trial protocol
• Previous inclusion in the present study
• Participation in a clinical study during the last 30 days

Department of Surgery or Department of Hemato-oncology in 36 hospitals