Letrozole in Preventing Breast Cancer in Healthy Postmenopausal Women at High Risk for Breast Cancer

Inclusion Criteria: * Healthy postmenopausal women at "high risk" for breast cancer will be eligible for the study; definition of menopause will be: * Amenorrhea for at least 12 months, or * History of hysterectomy and bilateral salpingo-oophorectomy, or * At least 55 years of age with prior hysterectomy with or without oophorectomy, or * Age 35 to 54 with a prior hysterectomy without oophorectomy OR with a status of ovaries unknown with documented follicle-stimulating hormone level demonstrating elevation in postmenopausal range * "High risk" for breast cancer will be defined as: * Prior histologically confirmed lobular carcinoma in situ (LCIS) treated by local excision only, or * At least 1.66% probability of invasive breast cancer within 5 years using the Breast Cancer Risk Assessment Tool * Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1; Karnofsky 80% or above * Leukocytes \>= 3,000/uL * Absolute neutrophil count \>= 1,500/uL * Platelets \>= 100,000/uL * Total bilirubin =\< 2.0 mg/dL * Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase \[SGOT\])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase \[SGPT\]) =\< 2.0 X institutional ULN * Creatinine =\< 1 X institutional ULN * Recent mammogram negative for breast cancer, Breast Imaging-Reporting and Data System (BIRADS) score \< 3 (within the last 12 months) * Ability to understand and the willingness to sign a written informed consent documen…