Analyzing a New Mechanism in Response to Tamoxifen Therapy in Breast Cancer Patients

This study will help to understand the interaction between the hormonal therapy Tamoxifen, estrogen receptors and certain genes in the cancer cell. This information may eventually help select the appropriate therapy for future patients with similar cancer.

Women with abnormal mammogram or suspicious masses will undergo diagnostic core biopsies which will be analyzed for ER/PR and HER2Neu expression. For patients that are ER positive, P53 staining will be done.

Women presenting tumors with an Allred score of 3 or greater status will be approached to participate.

Women will be randomized to either standard of care surgical therapy or a 4 week intervention of Tamoxifen 20mg daily for 4 weeks prior to surgery. During the intervention, blood draws will be done to measure levels of tamoxifen metabolites in the blood and test for polymorphisms that may decrease levels of active metabolites.

Women will undergo two blood draws for PK/PD and one for pharmacogenomics.

• No Intervention: No Intervention
• Active Comparator: Tamoxifen
  Tamoxifen 20 mg orally 1x/day for 4 weeks
  Intervention: Drug: Tamoxifen

Inclusion Criteria:

• The patient must consent to be in the study and must have signed an approved consent form conforming to institutional guidelines
• The patient must be 18 years or older
• Core biopsy should definitively demonstrate invasive carcinoma
• Invasive carcinoma should be ERά receptor positive
• The tumor should be approximately 1 cm, but at least 5mm to account for variability in imaging and imaging occult disease(physical exam, mammography, ultrasound).
• Patients in whom surgical excision of the tumor is part of standard of care management
• ECOG of 0 or 1
• Negative serum or urine β-hCG pregnancy test at screening for patients of child-bearing potential(this is routinely done if premenopausal and having surgery)
• Consent to participate in DBBR

Exclusion Criteria:

• Male patients are not eligible for this study
• Female patients with inoperable tumor and patients undergoing neo-adjuvant chemotherapy
• Patients with diagnosis by FNA cytology
• Pregnant or lactating women
• Prior therapy for breast cancer, including irradiation, chemo-, immuno- and/or hormonal therapy
• Patients receiving any hormonal therapy, e.g., birth-control pills, ovarian hormonal replacement therapy, infertility medications, etc. are not eligible
• Nonmalignant systemic disease (cardiovascular, renal, hepatic, etc.) that would preclude the patients from being subjected to surgical excision
• Psychiatric or addictive disorders that would preclude obtaining informed consent
• Patients known or suspected to have hypercoagulable syndrome or history of venous or arterial thrombosis, stroke, TIA, or pulmonary embolism
• Women who are post-menopausal defined as no menses for at least 12 months
• Women on selective serotonin reuptake inhibitors (SSRI) SSRI inhibits metabolism of tamoxifen
• Women with non-invasive disease or microinvasion are not eligible
• Women undergoing neoadjuvant chemotherapy are not eligible
• Women currently on tamoxifen for prevention are not eligible
• Patients shall not receive any herbal/alternative therapies such as flaxseed or soy products or black cohosh.
• Patients with a known mutation in p53 (Li Fraumeni Syndrome)

• National Institutes of Health (NIH)
• National Cancer Institute (NCI)