Adjuvant Treatment in Premenopausal Breast Cancer

Inclusion Criteria: 1. Female, premenopausal and ≥18 years age patients. 2. Agree to participate in study and signing informed consent or declaration in lieu of informed consent form, if applicable 3. Histological diagnosis of early breast cancer hormone positive (ER and/or PgR), HER2-negative. 4. Pathological nodal stage of pN0 or pN1 (1-3 nodes) and pathological tumor stage of pT1 to pT3. 5. Surgery for primary breast cancer and axillary staging by sentinel node biopsy or axillary lymph node dissection (ALND). 6. Availability of 21-multigene assay Oncotype DX recurrence score results performed according to physician choice from 1st January 2013 to 31st December 2022 7. Availability of clinical and pathological information. 8. Availability of information about adjuvant treatment received. 9. Availability of patient' outcome information (relapse, site of relapse, survival). Exclusion Criteria: 1. Evidence of distant metastases 2. Inflammatory breast cancer 3. Neoadjuvant treatment 4. No surgery for primary breast cancer and axillary staging 5. Patients not tested with 21-multigene assay Oncotype DX