Letrozole or Tamoxifen in Treating Postmenopausal Women With Breast Cancer

Inclusion Criteria

• •DISEASE CHARACTERISTICS:
• •Histologically confirmed resectable adenocarcinoma of the breast
• •* pT1, pT2, pT3, or minimal dermal involvement on pathology only
• •* pN0, pN1, pN2, or M0
• •* Negative nodal status
• •* At least 8 nodes are negative
• •* Unknown nodal status
• •* Less than 8 nodes examined and no pathological finding
• •* Positive nodal status
• •* Any positive finding independent of the number of nodes examined
• •* Negative sentinel node or no prior nodal dissection allowed if all other criteria met
• •Must have had total mastectomy, lumpectomy, or quadrantectomy
• •* Should have prior chest wall radiotherapy after segmental mastectomy or histopathologic T4 dermal involvement
• •Stage I, II, or IIIa allowed if the tumor is completely removed macroscopically and margins of the resected tumor are microscopically free of tumor
• •Must undergo chest wall radiotherapy or second resection if microscopic disease at the mastectomy margins
• •No bilateral disease except in situ disease, either ductal or lobular of the contralateral breast
• •Postmenopausal
• •* Regardless of prior hormonal replacement therapy (HRT) or hysterectomy:
• •* Bilateral oophorectomy and any age
• •* Radiologic castration and amenorrheic for at least 3 months and any age
• •* Not postmenopausal at the start of adjuvant chemotherapy AND and completed at least 6 courses of prior cyclophosphamide, methotrexate, and fluorouracil (CMF) or at least 4 courses of prior anthracycline-cyclophosphamide continuation therapy and at least age 45 with follicle stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) postmenopausal levels
• •* No prior HRT:
• •* Prior hysterectomy and less than age 55 with FSH/LH/E2 postmenopausal levels
• •* Prior hysterectomy and at least age 55
• •* No prior HRT or hysterectomy:
• •* Amenorrhea more than 1 year and less than age 50
• •* Amenorrhea more than 6 months and at least age 50
• •* Prior HRT regardless of hysterectomy:
• •* At least 1 month since prior HRT and less than age 55 with FSH/LH/E2 postmenopausal levels
• •* At least 1 month since prior HRT and at least age 55
• •* FSH/LH/E2 postmenopausal levels and uncategorized
• •No distant metastases, including bone scans showing hot spots unconfirmed as benign disease or skeletal pain of unknown cause
• •At least 10% hormone receptor-positive tumor cells
• •Hormone receptor status:
• •* Estrogen receptor positive AND/OR
• •* Progesterone receptor positive
• •PATIENT CHARACTERISTICS:
• •Age:
• •30 and over
• •Sex:
• •Female
• •Menopausal status:
• •Postmenopausal
• •Performance status:
• •Not specified
• •Life expectancy:
• •Not specified
• •Hematopoietic:
• •WBC greater than 3,000/mm\^3
• •Platelet count at least 100,000/mm\^3
• •Hemoglobin greater than 10 g/dL
• •Hepatic:
• •Bilirubin less than 3.0 mg/dL
• •SGOT or SGPT less than 1.5 times upper limit of normal
• •No hepatic disease that would preclude study
• •Renal:
• •Creatinine less than 1.8 mg/dL
• •No renal disease that would preclude study
• •Cardiovascular:
• •No cardiovascular disease that would preclude study
• •Prior deep vein thrombosis allowed if medically stable
• •Pulmonary:
• •No lung embolism
• •Other:
• •No other prior or concurrent malignancy within the past 5 years except adequately treated basal or squamous cell skin cancer or carcinoma in situ of the cervix
• •No prior noncompliance to medical regimens
• •No other nonmalignant systemic diseases that would preclude follow-up
• •HIV negative
• •PRIOR CONCURRENT THERAPY:
• •Biologic therapy:
• •Prior immunotherapy or biological response modifiers (e.g., interferon) allowed
• •Chemotherapy:
• •See Disease Characteristics
• •Prior adjuvant or neoadjuvant chemotherapy allowed
• •Concurrent adjuvant chemotherapy allowed
• •Endocrine therapy:
• •See Disease Characteristics
• •Prior neoadjuvant hormonal therapy allowed (e.g., antiestrogens, progestins, or aromatase inhibitors) if no more than 4 months duration and no disease progression
• •Prior corticosteroids allowed
• •At least 4 weeks since prior HRT
• •Prior adjuvant antiestrogen therapy allowed if less than 1 month duration and immediately after surgery, radiotherapy, and/or chemotherapy
• •Prior antiestrogens for chemoprevention allowed if at least 18 months between completion of chemoprevention and diagnosis
• •No other concurrent antiestrogens or aromatase inhibitors
• •No concurrent raloxifene
• •No concurrent systemic HRT with or without progestins of more than 3 months duration
• •Radiotherapy:
• •See Disease Characteristics
• •Concurrent radiotherapy allowed
• •Surgery:
• •See Disease Characteristics
• •Other:
• •At least 30 days since prior systemic investigational drugs
• •At least 7 days since prior topical investigational drugs
• •Concurrent bisphosphonates allowed