The Performance of Patient Support Program in Early Stage Breast Cancer

Inclusion Criteria: * Provide signed and dated written Informed Consent * Have been taking upfront AI adjuvant therapy in line with current SmPC * Be capable of completing drug intake by herself * Be capable of understanding Chinese Exclusion Criteria: * Upfront adjuvant hormonal therapy by an AI to which upfront adjuvant indication has not been granted by SFDA * Upfront adjuvant AI medication which has exceeded over eight weeks * Previous adjuvant hormonal therapy for breast cancer lasting over 8 weeks other than AI * Involvement in the planning and conduct of the study (applies to both AstraZeneca staff or staff at the study site)