Combined Estrogen Blockade of the Breast With Exemestane and Raloxifene in Postmenopausal Women With a History of Breast Cancer Who Have No Clinical Evidence of Disease

Inclusion Criteria:

* Postmenopausal women with a history of AJCC Stage 0, I, II or III breast cancer, with no clinical evidence of disease, after completion of all planned adjuvant therapy. Patients must not have received anti-estrogen therapy as part of their adjuvant treatment. Patients with a history of invasive ER- and/or PR-positive breast cancer are eligible only if they have not received an anti-estrogen as part of adjuvant therapy, and they are at least 2 years from the time of their primary surgery.
* Patients must have completed all planned adjuvant therapy, including surgery, chemotherapy, and radiation therapy, at least 4 weeks prior to treatment. There is no limit as to the amount of time that may have passed since completion of adjuvant therapy and initiation of treatment.
* Patients must be postmenopausal, as defined by either:

  1. No spontaneous menses for at least 5 years; women who have had a hysterectomy in this group, but have intact ovaries must have luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels within the postmenopausal range
  2. Spontaneous menses within the past 5 years, but amenorrheic (e.g. spontaneous or secondary to chemotherapy, radiation therapy or hysterectomy) for at least 12 months, and luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels within the postmenopausal range
  3. Bilateral oophorectomy
* Patients must have a history of breast cancer confirmed by the Department of Pathology at Memorial Sloan-Kettering Cancer Center.
* Patients must be at least 18 years old, and must be able to give written informed consent.
* Karnofsky performance status \> 80%.
* Laboratory parameters:

WBC =\>3.0 x 106 cells/ml serum bilirubin \<= 1.5 mg/dl serum creatinine \<= 1.5 mg/dl serum AST (SGOT) \<= 2x upper institutional normal CEA and CA15-3 within institutional normal limits

Exclusion Criteria:

* Prior history of bilateral mastectomy.
* Prior history of ovarian or endometrial cancer.
* Prior or current history of osteoporosis, as defined by a lumbar-spine bone mineral density \< 2.5 SD below the mean value for normal premenopausal women.
* Use of bisphosphonates or calcitonin within the past 3 months.
* Prior history of venous thrombosis or pulmonary embolism.
* Patients with unstable angina or New York Heart Association Class III or IV heart disease.
* Prior hormonal therapy within the past 3 months.