OBJECTIVES: Primary * Compare the efficacy of adjuvant tamoxifen vs anastrozole, in terms of local control and prevention of contralateral disease, in postmenopausal women with locally excised ductal carcinoma in situ. * Compare side effect profiles of these drugs in these patients. Secondary * Compare the efficacy of these drugs, according to the receptor status of the primary or recurrent cancer in these patients. * Compare the rate of breast cancer recurrence and growth of new contralateral tumors after cessation of treatment with these drugs in these patients. * Compare breast cancer mortality in patients treated with these drugs. * Compare the effect of these drugs on other cancers, cardiovascular disease, fracture rates, and non-breast cancer deaths in these patients. * Compare the tolerability and acceptability of side effects experienced by patients treated with these drugs. OUTLINE: This is a randomized, double-blind, multicentre study. Patients are stratified according to participating centre. Patients are randomized to 1 of 2 treatment arms. * Arm I: Patients receive oral tamoxifen and oral placebo once daily. * Arm II: Patients receive oral anastrozole and oral placebo once daily. In both arms, treatment continues for 5 years in the absence of disease recurrence or unacceptable toxicity. Patients are followed annually for 5 years and a further 5 years (minimum) off treatment. Peer Reviewed and Funded by Cancer Research UK. Sponsored by Queen Mary University of London ACTUAL ACCRUAL: A total of 2,980 patients were accrued for this study over 9 years.
DISEASE CHARACTERISTICS: * Diagnosis of ductal carcinoma in situ within the past 6 months * Locally excised with tumor-free margins at least 1 mm * Hormone receptor status: * Estrogen or progesterone receptor positive * Equal to or greater than 5% positive cells PATIENT CHARACTERISTICS: Age * 40 to 70 Sex * Female Menopausal status * Postmenopausal, defined as meeting at least 1 of the following criteria: * Over age 60 * Prior bilateral oophorectomy * Age 60 or under with a uterus AND amenorrhea for at least the past 12 months * Age 60 or under without a uterus AND follicle-stimulating hormone greater than 20 IU/L Performance status * Not specified Life expectancy * At least 10 years Hematopoietic * Not specified Hepatic * Not specified Renal * Not specified Cardiovascular * No prior deep vein thrombosis * No prior transient ischemic attack * No prior cerebrovascular accident Pulmonary * No prior pulmonary embolism Other * No unexplained postmenopausal bleeding * No other cancer within the past 5 years except nonmelanoma skin cancer or carcinoma in situ of the cervix * No other concurrent medical condition that would preclude study therapy, place the patient at unusual risk, or confound study results * No evidence of osteoporosis * Fragility fractures within the spine allowed if T-score level is greater than -4 and consist of no more than 2 fractures * Psychologically and physically suitable for 5 years of study therapy PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * Not specified Endocrine therapy * No prior or concurrent tamoxifen use lasting more than 6 months unless treatment was completed more than 5 years ago. Women in IBIS-I can join if off trial therapy for at least 5 years. * No prior or concurrent raloxifene use lasting more than 6 months unless treatment was completed more than 5 years ago. * No other prior or concurrent selective estrogen-receptor modulator use lasting more than 6 months unless treatment was completed more than 5 years ago * No concurrent systemic estrogen-based hormone replacement therapy, including vaginal estrogen preparations Radiotherapy * Not specified Surgery * See Disease Characteristics * No prior mastectomy * No planned prophylactic mastectomy Other * At least 3 months since prior unapproved or experimental agents * No concurrent anticoagulants
están designados en este estudio
de ser asignado al grupo placebo