Inclusion Criteria:

- Women age 18 years or older

- Pathological or histological confirmation of breast cancer at initial diagnosis or at
the time of metastases

- ECOG performance status of 0, 1 or 2 or Karnofsky performance status of 60 or higher

- Predicted life expectancy of 12 weeks or more

- Postmenopausal endocrine status. LH/FSH levels in the postmenopausal range in women
whose menopause occurred less than 5 years ago

- Locally recurrent, locally advanced, locally metastatic disease not amenable to
radiation therapy or surgery and/or distant metastatic disease

- At least one tumor localization measurable in 2 dimensions (one diameter at least 2
cm for soft tissue/visceral disease assessed by CT/MRI scan or conventional X-ray
technique, one diameter at least 1 cm for bone lesions assessed by conventional X-ray
techniques)

- Estrogen receptor and/or progesterone receptor positive (by laboratory/institutional
standard) at the time of initial diagnosis or determined during subsequent
biopsy/surgery of metastases

- Written informed consent obtained

Exclusion Criteria:

- Prior hormonal therapy to treat locally recurrent, locally advanced or metastatic
disease

- Prior adjuvant therapy with aromatase inhibitors or antiestrogens/SERMs within 12
months prior to enrollment

- Progression of disease during therapy with antiestrogens (including SERMs
administered for prevention of osteoporosis)

- Life-threatening locally recurrent, locally advanced or metastatic disease or disease
requiring chemotherapeutic intervention (such as inflammatory breast cancer)

- History of known CNS metastases, significant neurological dysfunction including
active seizures, or clinical signs of other significant neurological diseases

- Other active malignancy (except basal cell carcinoma of the skin or in situ cervical
cancer). Patients with previous malignancies must be without evidence of disease for
at least five years

- Renal insufficiency (serum creatinine > 2.0 mg/dL)

- Aspartate aminotransferase, alanine aminotransferase or serum bilirubin levels more
than 2.5 times upper limit of normal

- Hemoglobin <9 g/dL

- Platelet count of less than 100,000 platelets per mm3

- Total white blood cell count of less than 2,000 cells per mm3

- Premenopausal endocrine status; pregnant or lactating females

- Usage of an investigational drug within the thirty (30) days prior to enrollment; or
the planned usage of an investigational drug other than the study medication during
the course of the current study

- Contraindication to use of toremifene, atamestane, letrozole or any of the inactive
components of their formulations

- Prior enrollment in this study