PATIENT CHARACTERISTICS: Age: 70 and under Sex: Female Menopausal status: Postmenopausal, defined by 1 of the following criteria: Last menstrual period more than 1 year before initial surgery Any age with prior bilateral oophorectomy (for nonmalignant reason) Age 50 and over with prior hysterectomy (for nonmalignant reason) without oophorectomy If at variance with the above definitions, hormonal assays in postmenopausal range take precedence Performance status: Not specified Life expectancy: Not specified Hematopoietic: Not specified Hepatic: Not specified Renal: Not specified Other: No other serious illness No other prior invasive malignancy except adequately treated basal cell or squamous cell skin cancer