This is a French observational, national, multicenter prospective cohort study of patients with HER2-negative eBC treated with olaparib at their physician's discretion.

The purpose to this observational study is to evaluate the rate of completion of adjuvant Olaparib treatment for HER2-negative early breast cancer patients in France.

Inclusion Criteria:

• Male or female aged ≥ 18 years
• Patient diagnosed with HER2-negative eBC
• Patient about to be initiated with adjuvant Olaparib at their physician's discretion
• Patient has been informed and does not object to participation in the study.

Exclusion Criteria:

• Patient not consenting to participate.
• Patients included in the Early Access Program

Patients will be recruited from about 60 participating sites to reach the target of 126 subjects, with a maximum of 60% of subtype TN overall.