"Observational, Retrospective and Prospective, Non-interventional, Multicentre on the Use of Genomic Testing in the Management of Early Stage HR+/HER2- Breast Cancer"

The study is a retrospective and prospective, non-interventional, observational registry-based study that will enroll all patients with ER +/HER2-negative, T1-3 breast cancer with negative axillary lymph nodes or up to 3 positive axillary lymph nodes for whom Breast Units require genomic test to support adjuvant therapy decisions, according to current clinical practice. For prospective cohort: genomic tests will be performed on all patients who meet the criteria for access to testing as set out in the Ministerial Decree of 18/05/2021, unless otherwise agreed by the reference Breast Unit, in accordance with the specific diagnostic pathways activated by each site. For retrospective cohort: data for patient referred for genomic testing following Ministerial Decree 18/05/2021 will be collected. The patient's baseline demographic characteristics, tumor clinicopathological features, pre and post-test therapeutic indication (CET vs ET), the test results, the actual adjuvant treatment received and time around data will be recorded in a dedicated registry.

Inclusion criteria

• . Age ≥ 18 years
• PS ECOG 0-1
• Histologically confirmed early breast carcinoma with positivity for hormone receptors (ER+ IHC >10%) and HER2 negative (IHC value 0 1+ and/or FISH not-amplified)
• Primary resective surgery for early breast cancer with adequate assessment of lymph node status (sentinel lymph node biopsy or complete axillary dissection), with one of the following diagnostic stages:

• T1-3, N0, M0
• T1-3, pN1mic, M0
• T1-3, pN1a, M0
• Indication for adjuvant treatment with endocrine therapy (ET) or chemo endocrine therapy (CET), according to the decision of the reference Breast Unit
• Meeting the criteria for "intermediate" risk, i.e., no "low" or "high" risk of recurrence, as defined in the ministerial decree of 18/05/21:

• Low risk defined by at least 5 of the following: G1, T1a-b, KI67 < 15, N neg, ER > 80%
• High risk, defined by at least 4 of the following: G3, T > 2, Ki67 > 30, N pos, ER < 30%
• Indication for genomic test (Oncotype DX®, Mammaprint®, PAM50 Prosigna®, Breast Cancer Index®, EndoPredict®) by the Breast Unit
• Ability to provide written informed consent to participate in the registry study, approved by the local Ethics Committee.
• The patient underwent genomic testing starting from September 2021

Exclusion criteria

• Low-risk and High-risk patients as defined in the Ministerial Decree of 18/05/21
• ER negative and/or HER2 positive tumours
• More than 3 lymph nodes involved at clinical/pathological staging
• Invasive tumours <2mm evaluated by local pathologists
• Previous history of breast cancer
• Synchronous breast cancers
• Multifocal tumours
• Metastatic disease
• Contraindications to adjuvant treatments
• Performance status (PS ECOG) > 1 and / or other clinical factors that would make the patient a candidate and unsuitable for systemic adjuvant treatment or have received an exclusive indication for precautionary hormone therapy as part of the Breast Unit collegial assessment.
• Psychiatric diagnosis that may affect the ability to participate in this study