Exemestane in Treating Postmenopausal Women With Stage IV Breast Cancer

Inclusion Criteria

• •Histologically or cytologically confirmed metastatic carcinoma of the breast
• •Hormone receptor (estrogen receptor \[ER\] and/or progesterone receptor \[PR\]) positive disease (defined as: ER and/or PR positivity as \>= 5% staining), as confirmed by immunohistochemistry (IHC) based on primary breast tissue or metastatic tissue
• •Postmenopausal, as defined by any of the following:
• •Natural menopause, with at least 1 year since last menses
• •Chemotherapy-induced menopause with at least 1 year from last menses and serum luteinizing hormone (LH)/follicle-stimulating hormone (FSH) and estradiol levels within the postmenopausal range
• •History of surgical or radiation-induced ovarian ablation
• •For women =\< 56 years old and with a history of hysterectomy but at least one ovary intact, serum LH/FSH and estradiol levels must be within the postmenopausal range
• •Postmenopausal women with disease recurrence while receiving either tamoxifen or a non-steroidal aromatase inhibitor (AI) as adjuvant therapy (as long as adjuvant hormonal therapy was taken for 6 months before disease progression) or with disease recurrence following the discontinuation/completion of adjuvant hormonal therapy
• •Postmenopausal women with disease progression following either 0, 1 or 2 prior hormonal therapies for metastatic breast cancer, as long as the subject has had no prior exposure to exemestane (EXE)
• •Measurable or non-measurable (but evaluable) disease, as defined by RECIST criteria
• •Eastern Cooperative Oncology Group (ECOG) performance status of 0-1
• •Neutrophil count \>= 1.5 X 10\^9 cells/L
• •Platelet count \>= 100 X 10\^9 cells/L
• •Serum creatinine =\< 1.5 times upper limit of normal (ULN)
• •Total serum bilirubin =\< 1.5 times ULN
• •Aspartate aminotransferase (AST)/alanine aminotransferase (ALT) levels =\< 2.5 x ULN in patients without liver metastases or =\< 5 times ULN in patients with liver metastases
• •Alkaline phosphatase =\< 2.5 times the ULN for patients without bone or liver metastases
• •Subjects must have an estimated life expectancy of greater than 6 months