Prospective Observational Study Evaluating Treatment Decision Impact of Prosigna® in Early Stage Breast Cancer Patients

Inclusion Criteria

• •Surgically resected node-negative, estrogen receptor-positive, HER2-negative early-stage invasive breast cancer (T1-T2, N0, pN0 (i+), pN0 (mol+), M0)
• •1. Estrogen receptor status will be evaluated by Immunohistochemistry (IHC) and more than 1% of stained tumor cells will be considered positive.
• •2. HER2 status will be evaluated by IHC and/or by in-situ fluorescence hybridization (0 or 1+, or 2+ will be considered negative in the absence of in-situ fluorescence hybridization).
• •Postmenopausal females, which is defined as:
• •1. Natural Amenorrhea \> 12 months, regardless of age
• •2. Bilateral oophorectomy, regardless of age (the oophorectomy must have been carried out at least 4 weeks before entering the study)
• •3. Radiological castration with amenorrhea \> 3 months, regardless of age
• •4. Hysterectomy and postmenopausal blood levels of FSH/LH
• •Able to give informed consent
• •Eligible for treatment of breast cancer with adjuvant chemotherapy, as determined by the treating physician
• •ECOG performance status of 0 or 1