Multicentric retroprospective observational study to collect outcome in premenopausal breast cancer patients who undergone the 21-multigene assay Oncotype DX from 1st January 2013 to 31st December 2022 and adjuvant treatment.

Premenopausal patients who undergone the 21-multigene assay Oncotype DX from 1st January 2013 to 31st December 2022 with any Recurrence Score (RS) and pathological nodal status pN0/pN1 will be included in the study. The study will collect clinical-pathological, genomic characteristics, adjuvant treatments (chemotherapy, endocrine therapy with/without OFS), and survival outcome (iDFS).

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

Female

Patients with premenopausal early breast cancer HR+ HER2 negative diagnosis with any Recurrence Score (RS) and pathological nodal status pN0/pN1 and who underwent the 21-multigene assay Oncotype DX from 1st January 2013 to 31st December 2022 and adjuvant treatment.