• Histological diagnosis of HR+/HER2- early breast cancer with curative intent

• Patients must have an indication for a treatment with ribociclib + AI ± LHRH as described in the current SmPC/Fachinformation of ribociclib (to be included into the cohorts of ribociclib + AI ± LHRH and ET mono ± LHRH) or abemaciclib + ET ± LHRH as described in the current SmPC/Fachinformation of abemaciclib (to be included into the abemaciclib + ET ± LHRH cohort) in the adjuvant setting

• Before enrollment the treating physician has made the decision in accordance with the patient to treat the patient with either

‣ ribociclib + AI ± LHRH, or

⁃ ET mono ± LHRH, or

⁃ abemaciclib + ET ± LHRH and baseline is no longer than 2 weeks (14 days) prior to written informed consent for this study.

∙ Baseline = for ribociclib + AI ± LHRH cohort: date of therapy start; for abemaciclib + ET ± LHRH cohort: date of therapy start; for ET mono ± LHRH cohort: within 4 weeks after therapy start or within 4 weeks after last non-endocrine based therapy, whichever is last.

• ≥18 years of age

• Written informed consent