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