Chemotherapy or Letrozole Before Surgery in Treating Postmenopausal Women With Breast Cancer That Can Be Removed By Surgery

DISEASE CHARACTERISTICS:

* Histologically proven primary invasive breast cancer that is thought to be suitable for neoadjuvant treatment

  * No cytological proof of malignancy only
  * T2 tumor or greater (≥ 20 mm by ultrasound) or any T stage with nodal disease ≥ 20 mm diameter on ultrasound assessment
  * No evidence of distant metastatic disease as disclosed by bone scan, liver, and chest imaging
* Definite indication for neoadjuvant and adjuvant chemotherapy
* Primary tumor amenable to biopsy
* No inoperable disease that is judged very unlikely to be rendered operable by neoadjuvant treatment
* No inflammatory breast cancer
* No bilateral invasive breast cancer
* HER-2 positivity is NOT an exclusion criterion in the feasibility (pilot) study
* Estrogen receptor (ER) positive tumor

  * No ER-poor disease as defined locally (e.g., H-score \< 100, Allred 3/4/5)
  * Allred 6/7/8, H-score H ≥100 allowed

PATIENT CHARACTERISTICS:

* Postmenopausal, meeting 1 of the following criteria:

  * Over 12 months since last menstrual period
  * Postmenopausal gonadotrophin levels (luteinizing hormone or follicle-stimulating hormone levels above local criteria)
  * Postmenopausal estradiol levels below local criteria
  * Prior bilateral oophorectomy
  * Menopause induced by gonadotrophin-releasing hormone not allowed
* WHO performance status 0 or 1
* WBC ≥ 3.0 × 10\^9/L
* ANC ≥ 1.5 × 10\^9/L
* Platelets ≥ 100 × 10\^9/L
* Hemoglobin \> 9 g/dL
* AST/ALT ≤ 1.5 times upper limit of normal (ULN)
* Serum bilirubin ≤ 1.5 times ULN
* Alkaline phosphatase ≤ 1.5 times ULN
* Serum creatinine ≤ 1.5 times ULN
* No active, uncontrolled infection
* No malignancy within the past 10 years except for basal cell carcinoma or cervical carcinoma in situ

  * Treatment for previous malignancy confined to resection alone
* No concomitant medical, psychiatric, or geographic problems that might prevent completion of treatment or follow-up
* No known severe hypersensitivity to aromatase inhibitors
* No contraindication to receiving aromatase inhibitors (clinical evidence or recorded history of osteoporosis)
* No other serious illness or medical condition including any of the following:

  * Congestive heart failure or unstable angina pectoris
  * Myocardial infarction within the past year
  * Uncontrolled hypertension or high-risk uncontrolled arrhythmias
  * History of significant neurologic or psychiatric disorders, including psychotic disorders, dementia, or seizures, that would prohibit the understanding and giving of informed consent
  * Active peptic ulcer
  * Unstable diabetes mellitus
* No definite contraindications for the use of corticosteroids
* No contraindication to receiving combination anthracycline/taxane chemotherapy
* Willing to undergo repeat biopsies

PRIOR CONCURRENT THERAPY:

* No hormone replacement therapy within 4 weeks of starting treatment
* No chronic oral treatment with corticosteroids unless initiated \> 6 months prior to study entry and at low dose (≤ 20 mg methylprednisolone or equivalent)
* No concurrent warfarin or heparin therapy