• Change in number of daily hot flashes at 3 months from baseline
• Change in hot-flash score at 3 months from baseline

RATIONALE: Soy protein supplement may be effective in reducing hot flashes in postmenopausal women who are receiving tamoxifen for breast disease.

PURPOSE: Randomized phase II trial to determine the effectiveness of soy protein supplement in reducing hot flashes in postmenopausal women who are receiving tamoxifen for breast disease such as ductal hyperplasia or breast cancer.

OBJECTIVES:

• Compare the effect of soy protein vs placebo on the daily number and severity of hot flashes in postmenopausal women with breast disease taking tamoxifen.
• Compare the quality of life in patients treated with these regimens.
• Compare the time to first relief of hot flashes in patients treated with these regimens.
• Compare the effect of these regimens on hormonal change in these patients.

OUTLINE: This is a randomized, double-blind, placebo-controlled, multicenter study. Patients are stratified according to duration of hot flashes (less than 9 months vs 9 months or more) and frequency of hot flashes (7 to 9 per day vs more than 9 per day).

Patients receive oral placebo once per day and keep a hot flash diary daily for 1 week and are then randomized to 1 of 2 treatment arms.

• Arm I: Patients receive oral soy supplement once daily for 12 weeks.
• Arm II: Patients receive oral placebo once daily for 12 weeks. Patients on both arms complete a daily hot flash diary.

Quality of life is assessed at baseline and at weeks 6 and 12.

Patients are followed for 3 months.

PROJECTED ACCRUAL: A total of 130 patients (65 per treatment arm) will be accrued for this study within 9 months.

• Breast Cancer
• Hot Flashes

• Dietary Supplement: soy protein isolate
• Other: placebo

• Experimental: Patients receive oral soy supplement once daily for 12 weeks.
• Placebo Comparator: Patients receive oral placebo once daily for 12 weeks.

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