BIG 1-98A Phase III Study to Evaluate Letrozole as Adjuvant Endocrine Therapy for Postmenopausal Women With Receptor (ER and/or PgR) Positive Tumors

Study start date: March 1, 1998

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