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