Hormone Replacement Therapy for Hot Flashes and/or Vaginal Symptoms in Postmenopausal Women Receiving Tamoxifen for Breast Cancer

DISEASE CHARACTERISTICS: Histologically confirmed node-negative invasive carcinoma or ductal carcinoma in situ of the breast No contralateral breast cancer No recurrent or metastatic disease Completion of active non-hormonal therapy for breast cancer Receiving tamoxifen (20 mg/day) for at least 3 months prior to study and plan to continue drug while on study Hot flashes severe enough to seek medical intervention (at least 7-8 moderate to severe hot flashes per day or 60 per week at baseline) AND/OR Vaginal symptoms, including dyspareunia, vaginal dryness, irritation, or thinning due to estrogen deficiency If uterus present, no prior histologically confirmed adenomatous or atypical endometrial hyperplasia or endometrial carcinoma AND no concurrent endometrial cancer confirmed by pelvic exam within the past year No active endometriosis No unexplained vaginal bleeding Hormone receptor status: Estrogen and progesterone receptor status known for patients with invasive breast cancer PATIENT CHARACTERISTICS: Age: 18 and over Sex: Female Menopausal status: Postmenopausal No menstrual period for more than 12 months OR prior bilateral oophorectomy Must be over 55 years of age OR have documented follicle-stimulating hormone levels in postmenopausal range if one or both ovaries remain after prior hysterectomy Performance status: ECOG 0-1 Life expectancy: Not specified Hematopoietic: Not specified Hepatic: Not specified Renal: Not specified Cardiovascular: No prior superficial or deep venous or arterial thrombosis No serious venous stasis disease Pulmonary: No pulmonary embolus Other: Must be able to read and speak English No lower extremity trauma, swelling, or tenderness within the past 4 weeks No active gallbladder disease No migraine headaches No other prior malignancy unless curatively treated with no evidence of recurrence No concurrent seizure disorder requiring anti-seizure medication PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: Not specified Endocrine therapy: See Disease Characteristics No other concurrent estrogen or hormone replacement therapy No concurrent clonidine, bellergal, progestational agent, or methyldopa for hot flashes No concurrent topical vaginal estrogen cream (e.g., Estring or Vagifem) for patients with vaginal symptoms only Radiotherapy: Not specified Surgery: At least 4 weeks since prior surgery Other: At least 12 months since prior treatment for congestive heart failure Concurrent selective serotonin reuptake inhibitors (SSRI) or antidepressants with SSRI activity allowed if begun at least 3 months prior to study and continue during study