Eligibility Criteria

• Disease Characteristics
  • Histologically confirmed adenocarcinoma of the breast
    • Stage III (locally advanced), metastatic, or recurrent disease
    • Deemed not resectable
  • Estrogen-receptor and/or progesterone-receptor positive disease
    • Receptor status is based on most recent results
    • Receptor testing on metastatic disease is not required
  • Measurable or non-measurable disease
  • History of CNS metastasis allowed provided it has been treated (surgery, radiotherapy, or radiosurgery) within the past 4 weeks and does not require medications to control symptoms
    • No known leptomeningeal disease allowed
• Patient Characteristics
  • ECOG performance status 0-2
  • Menopausal status not specified
  • Total bilirubin ≤ 1.5 times upper limit of normal (ULN)
  • ALT and AST ≤ 2.5 times ULN (≤ 5 times ULN if liver metastases present)
  • Not pregnant or nursing
  • Negative pregnancy test
  • Fertile patients must use effective nonhormonal contraception
  • No medical or psychiatric conditions that would interfere with protocol compliance, the ability to provide informed consent, assessment of response, or anticipated toxicities
  • More than 5 years since prior invasive malignancies except curatively treated basal cell or squamous cell carcinoma of the skin or carcinoma in situ of the cervix
• Prior Concurrent Therapy
  • See Disease Characteristics
  • No prior investigational agents in the metastatic setting
  • Other prior investigational agents in any setting must have been completed at least 6 weeks prior to study registration and should be discussed with the study PI
  • Prior tamoxifen as adjuvant treatment is allowed as long as the patient did not have disease relapse or progression while on adjuvant tamoxifen or within 4 weeks of last dose
    • Prior tamoxifen for advanced disease is not allowed
    • No prior chemotherapy or trastuzumab (Herceptin) for metastatic disease
  • Prior chemotherapy, trastuzumab, or bevacizumab in the adjuvant setting allowed provided it has been completed ≥ 4 weeks before study therapy
  • Must not have had more than 2 lines of non-hormonal treatment in the locally advanced or metastatic setting, including trastuzumab (Herceptin), bevacizumab, or other biologics
  • Treatment in the advanced setting must have been completed at least 2 weeks prior to study initiation
  • Prior aromatase inhibitors (e.g., anastrozole, letrozole, exemestane, aminoglutethamide) are allowed in the adjuvant or metastatic setting
  • At least 2 weeks since prior and no concurrent medications that are strong to moderate inhibitors of CYP2D6 and may alter tamoxifen citrate metabolism including, but not limited to
    • Paroxetine (Paxil)
    • Fluoxetine (Prozac)
    • Bupropion (Wellbutrin)
    • Quinidine (Cardioquin)
  • May not initiate bisphosphonate therapy while receiving treatment on this study
    • If have begun receiving bisphosphonate therapy prior to registration may continue at the same intervals used prior to study registration
  • Concurrent radiotherapy to painful sites of bone disease or areas of impending fractures allowed provided the following criteria are met:
    • Radiotherapy was initiated before study entry
    • Sites of measurable or non-measurable disease are outside the radiotherapy port
    • Recovered from prior radiotherapy
  • No other concurrent hormonal therapy
  • No concurrent chemotherapy