Clinical Trials

Inclusion Criteria - Registration:

• Disease characteristics:
  • Histological confirmation of invasive breast carcinoma.
  • Stage I-III breast cancer.
  • Estrogen receptor (ER) positive disease according to American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines as ER ≥ 1% positive nuclear staining.
• Completion of all planned cancer treatments ≤ 60 days prior to registration:
  • Surgical resection of breast and nodal surgery;
    • NOTE: Reconstructive surgery does not have to be completed.
  • Adjuvant radiation therapy, if needed; and
  • Neoadjuvant and/or adjuvant chemotherapy, if needed.
• Post-menopausal defined as:
  • Age ≥ 60 and amenorrhea > 12 consecutive months; OR
  • Previous bilateral oophorectomy; OR
  • Age < 60 and amenorrhea > 12 consecutive months and documented follicle stimulating hormone (FSH) level within post-menopausal range according to institutional standard.
    • NOTE: Patients who did not meet these criteria at time of diagnosis and received pre-operative (neoadjuvant) or post-operative (adjuvant) chemotherapy will not be allowed to participate.
• Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0, 1, or 2.
• Hemoglobin ≥ 8.0 g/dL (obtained ≤ 14 days prior to registration).
• Absolute neutrophil count (ANC) ≥ 1500/mm^3 (obtained ≤ 14 days prior to registration).
• Platelet count ≥ 70,000/mm^3 (obtained ≤ 14 days prior to registration).
• Total bilirubin ≤ 1.5 x upper limit of normal (ULN) (obtained ≤ 14 days prior to registration).
• Alanine aminotransferase (ALT) and aspartate transaminase (AST) ≤ 3 x ULN (obtained ≤ 14 days prior to registration).
• Ability to swallow oral medication -Provide written informed consent.
• Willingness to provide mandatory blood specimens for correlative research. 
• Willing to return to enrolling institution for follow-up (during the Active Monitoring Phase of the study).
• Additional Inclusion Criteria - Pre-Registration may apply.

Exclusion Criteria - Registration:

• Pre-menopausal women receiving ovarian function suppression (goserelin, leuprolide, etc.).
• Stage IV (metastatic) breast cancer.
• HER2 positive breast cancer as defined by:
  • HER2 immunohistochemistry (IHC) ≥ 3+;
  • HER2/CEP17 ≥ 2.0;
  • HER2/CEP17 < 2.0  and average HER2 copy number of ≥ 6.0 signals/cell.
• Prior endocrine therapy for this breast cancer.
• Currently receiving any of the following cancer-directed therapies:
  • Radiation therapy
  • Systemic therapy such as chemotherapy (standard or investigational)
• Bisphosphonate therapy started < 4 weeks prior to registration.
  • NOTE: If patient is currently on bisphosphonate therapy she must be on stable dose for ≥ 4 weeks prior to registration. Patients not currently taking bisphosphonates will be allowed to start bisphosphonate therapy after completion of anastrozole (1mg and 10 mg daily [if given]). Information regarding bisphosphonate therapy will be collected.
• Current use of systemic or topical exogenous estrogen or progesterone (menopausal hormone replacement therapy [HRT]).
• Additional Exclusion Criteria may apply.