Inclusion Criteria:

- Postmenopausal women with hormone sensitive early breast cancer.

- Documented decision of treatment with anastrozole which will start in 13 weeks
according to current SmPC OR current treatment with anastrozole according to current
SmPC, that has not exceeded thirteen weeks before enrollment.

- Subjects who accept to use MEMS® monitors to automatically compile their drug dosing
histories.

Exclusion Criteria:

- Concomitant or previous use of adjuvant tamoxifen, letrozole or exemestane for the
current tumour.

- Involvement in the planning and/or conduct of the study (applies to both AstraZeneca
staff or staff at the study site).

- Participation in another clinical study with an investigational product during the
last 3 months.