Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed breast disease, including one of the following:

- Atypical ductal hyperplasia

- Ductal carcinoma in situ

- Lobular carcinoma in situ

- Stage I, II, or IIIA invasive adenocarcinoma

- Must be taking tamoxifen on a daily basis

- Bothersome hot flashes, at least 7 per day for at least 1 month and severe enough to
make patient desire intervention

- Hormone receptor status:

- Not specified

PATIENT CHARACTERISTICS:

Age:

- 20 and over

Sex:

- Female

Menopausal status:

- Postmenopausal, defined by one of the following:

- Surgical menopause

- At least 1 year since prior menses

- Postmenopausal FSH levels

Performance status:

- CALGB 0-2

Life expectancy:

- Not specified

Hematopoietic:

- Not specified

Hepatic:

- Not specified

Renal:

- Not specified

Other:

- No prior soy or milk intolerance

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- Not specified

Chemotherapy:

- Prior adjuvant chemotherapy allowed

- No concurrent adjuvant chemotherapy

Endocrine therapy:

- See Disease Characteristics

- At least 4 weeks since prior progestational therapy

- No concurrent progestins (e.g., megestrol)

- No concurrent systemic hormone replacement therapy or vaginal estrogen creams

- Estradiol-releasing vaginal ring allowed

Radiotherapy:

- Prior radiotherapy allowed

- No concurrent radiotherapy

Surgery:

- Prior surgery allowed

- No concurrent surgery

Other:

- At least 4 weeks since prior vitamin E, clonidine, belladonna derivative, or soy
supplement for hot flashes

- At least 4 weeks since prior selective serotonin reuptake inhibitors for hot flashes

- Concurrent antidepressants allowed provided dose has been stable for at least 1 month
and the purpose is for other than control of hot flashes

- No concurrent vitamin E, clonidine, belladonna derivative, or other soy supplement
for hot flashes

- Concurrent low doses of vitamin E that are part of a multivitamin allowed

- No other concurrent soy products