Tamoxifen Citrate in Treating Patients With Metastatic or Recurrent Breast Cancer

Inclusion Criteria

• 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
• Measurable or non-measurable disease
• ECOG performance status 0-2
• History of central nervous system (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
• Total bilirubin ≤ 1.5 times upper limit of normal (ULN)
• Alanine transaminase (ALT) and aspartate transaminase (AST) ≤ 2.5 times ULN (≤ 5 times ULN if liver metastases present)
• Negative pregnancy test
• Fertile patients must use effective nonhormonal contraception
• Disease-free of prior invasive malignancies for ≥ 5 years with the exception of curatively-treated basal cell or squamous cell carcinoma of the skin or carcinoma in situ of the cervix
• Prior chemotherapy, trastuzumab, or bevacizumab in the adjuvant setting allowed provided it has been completed ≥ 4 weeks before study therapy; other prior non-hormonal investigational agents in the adjuvant setting must have been completed at least 4 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
• 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, any of the following:
• Paroxetine (Paxil)
• Fluoxetine (Prozac)
• Bupropion (Wellbutrin)
• Quinidine (Cardioquin)
• 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

Exclusion Criteria

• Pregnant or nursing
• Concurrent chemotherapy
• Leptomeningeal disease
• Non-protocol concurrent hormonal therapy
• Medical or psychiatric conditions that would interfere with protocol compliance, the ability to provide informed consent, assessment of response, or anticipated toxicities
• Prior tamoxifen for advanced disease
• More than 2 lines of non-hormonal treatment in the locally advanced or metastatic setting, including trastuzumab (Herceptin), bevacizumab, or other biologics
• Starting bisphosphonate therapy while receiving treatment on this study
• Patients who have begun receiving bisphosphonate therapy prior to registration may continue at the same intervals used prior to study registration