Clinical Research Directory

Inclusion Criteria (Summary): * ECOG performance status 0-2 * Diagnosed with anatomic stage I, ER positive, PR positive or negative, and HER2 non amplified invasive breast cancer and clinically negative nodes; any invasive breast cancer histologic subtype may be enrolled * Tumor size ≤ 2 cm * Patient has elected BCS as surgical choice * Eligible to receive tamoxifen or an aromatase inhibitor * Ability to take oral medication and be willing to adhere to the endocrine therapy for the 3 month period prior to BCS Exclusion Criteria (Summary): * Prior or current use of endocrine therapy for breast cancer * History of ipsilateral breast radiation * Pregnancy or lactation * Has a known additional malignancy that is progressing or requires active treatment. Exceptions include basal cell carcinoma of the skin or squamous cell carcinoma of the skin that has undergone potentially curative therapy or in situ cervical cancer. * Current or planned use of a strong CYP2D6 inhibitor (e.g. Fluoxetine, Paroxetine) and is not able to receive an endocrine therapy agent that does not use the CYP2D6 pathway