Letrozole in Treating Postmenopausal Women With Stage I, II or III Breast Cancer That Can Be Removed by Surgery

DISEASE CHARACTERISTICS:

• Diagnosis of invasive breast cancer
• Clinical stage I, II, or III disease
• Resectable disease
• Measurable disease, defined as a mass that can be reproducibly measured by physical examination and/or ultrasound and is at least 1 cm in size by ultrasound
• Patients with measurable residual tumor at the primary site allowed
• Estrogen receptor-positive tumor by immunohistochemistry (IHC)
• HER2-negative tumor by Herceptest (0 or +1) OR HER2 not overexpressed by fluorescence in situ hybridization (FISH)
• Planning to undergo surgical treatment with either segmental resection or total mastectomy with or without lymph node evaluation
• Must have core biopsies from the time of diagnosis available (may include sections of paraffin-embedded material)
• Prior contralateral breast cancer allowed provided there is no evidence of recurrence of the initial primary breast cancer
• Patients with locally advanced disease who are candidates for preoperative chemotherapy at the time of initial evaluation are not eligible
• Locally advanced disease is defined by any of the following:
• Primary tumor ≥ 5 cm (T3)
• Tumor of any size with direct extension to the chest wall or skin (T4a-c)
• Inflammatory breast cancer (T4d)
• Fixed axillary lymph node metastases (N2)
• Metastasis to ipsilateral internal mammary node (N3)
• No locally recurrent disease
• No evidence of distant metastatic disease (i.e., lung, liver, bone, or brain metastases)

PATIENT CHARACTERISTICS:

• ECOG performance status 0-1
• Postmenopausal, as defined by any of the following:
• 55 years of age and over
• Under 55 years of age and meets 1 of the following criteria:
• Amenorrheic for at least 12 months
• Follicle-stimulating hormone (FSH) ≥ 40 IU/L and estradiol levels ≤ 20 IU/L
• Has undergone prior bilateral oophorectomy or radiation castration AND has been amenorrheic for at least 6 months
• Bilirubin ≤ 1.5 times upper limit of normal (ULN)
• SGOT and SGPT ≤ 1.5 times ULN
• Creatinine ≤ 1.5 t times ULN
• Able to swallow and retain oral medication
• No serious medical illness that, in the judgment of the treating physician, places the patient at high risk for operative mortality
• No malabsorption syndrome, ulcerative colitis, or other disease significantly affecting gastrointestinal function
• No other malignancy within the past 5 years except for completely resected nonmelanoma skin cancer or successfully treated in situ carcinoma
• No dementia, altered mental status, or any psychiatric condition that would preclude the understanding or rendering of informed consent
• No severe uncontrolled malabsorption condition or disease (i.e., grade II/III diarrhea, severe malnutrition, or short gut syndrome)

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• At least 21 days since prior tamoxifen or raloxifene as a preventive agent
• At least 7 days since prior hormone replacement therapy (e.g., conjugated estrogens [Premarin])
• No prior resection of the stomach or small bowel
• More than 30 days or 5 half-lives, whichever is longer, since prior investigational drugs
• No prior chemotherapy for this primary breast cancer
• No other concurrent investigational agents
• No other concurrent anticancer therapy (e.g., chemotherapy, radiotherapy, immunotherapy, hormonal therapy, or any other biologic therapy)