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