DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed breast cancer in 1 of the following disease states:

  • Locally advanced
  • Locoregionally recurrent
  • Metastatic

• Documented disease progression on or after antiestrogen therapy, given in 1 of the following ways:

  • As adjuvant therapy (for at least 12 months)
  • As first-line therapy for advanced disease, on which the patient had an objective response (partial or complete) or stable disease for at least 6 months

• Measurable disease

  • If the sole indicator lesion is in a previously irradiated area, recurrence of the lesion must be biopsy proven

• No rapidly progressive, life-threatening metastases, including:

  • CNS metastases
  • Diffuse lymphangitis carcinomatosa of the lung
  • Metastases occupying more than 1/3 of the liver

• Hormone receptor status:

  • Estrogen receptor- or progesterone receptor-positive (i.e., primary or secondary tumor tissue positive by any assay)

PATIENT CHARACTERISTICS:

Age

• See Menopausal status

Sex

• Female

Menopausal status

• Postmenopausal, defined as any of the following:

  • Over 50 years of age and no menstruation for more than 12 months
  • Any age with castrate levels of follicle-stimulating hormone
  • Underwent prior bilateral oopherectomy

Performance status

• ECOG 0-2

Life expectancy

• Not specified

Hematopoietic

• Absolute neutrophil count normal
• Platelet count normal

Hepatic

• Bilirubin no greater than 2 mg/dL
• AST and ALT no greater than 2.5 times upper limit of normal (ULN)

Renal

• Creatinine no greater than 1.5 times ULN

Other

• No other malignancy within the past 5 years except contralateral breast carcinoma, basal cell or nonmetastatic squamous cell skin cancer, carcinoma in situ of the cervix, or stage I carcinoma of the cervix
• No symptomatic peripheral neuropathy
• No known or suspected allergy to letrozole or imidazole drugs (e.g., clotrimazole, ketoconazole, miconazole, econazole, fenticonazole, isoconazole, sulconazole, tioconazole, or terconazole)
• No coexisting medical condition that would interfere with study procedures and/or results

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• No more than 1 prior chemotherapy regimen, given as adjuvant therapy or for metastatic disease (not both)

Endocrine therapy

• See Disease Characteristics
• No prior systemic endocrine therapy (including aromatase inhibitors) except antiestrogen therapy (e.g., tamoxifen)

Radiotherapy

• See Disease Characteristics

Surgery

• Not specified

Other

• At least 30 days since prior participation in another investigational study
• No prior farnesyl transferase inhibitor therapy
• No other concurrent anticancer treatment
• Concurrent bisphosphonates allowed for bone metastases present at baseline