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Soy Isoflavones and Breast Cancer Risk Reduction

This study is ongoing, but not recruiting participants.
National Cancer Institute (NCI)
National Center for Research Resources (NCRR)
Information provided by (Responsible Party):
The University of Texas Medical Branch, Galveston Identifier:
First received: September 12, 2005
Last updated: May 10, 2016
Last verified: May 2016
Soy consumption has been associated with reduced risk for developing breast cancer. Soy contains isoflavones which are weak estrogens. The roles of soy isoflavones in reducing breast cancer risk are currently unclear. Breast density has been considered as a breast cancer risk marker. We hypothesize that because isoflavones have estrogen-like activities, breast density and possibly bone density will be lower in women on soy-isoflavones.

Condition Intervention Phase
Breast Cancer
Dietary Supplement: isoflavones
Dietary Supplement: carbohydrate
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Investigator)
Primary Purpose: Prevention
Official Title: Mammographic Density and Soy Isoflavones

Resource links provided by NLM:

Further study details as provided by The University of Texas Medical Branch, Galveston:

Primary Outcome Measures:
  • Breast density [ Time Frame: one or two years after dietary supplements ]

Secondary Outcome Measures:
  • bone density [ Time Frame: one or two years after dietary supplement ]

Enrollment: 187
Study Start Date: April 2004
Estimated Study Completion Date: December 2017
Estimated Primary Completion Date: December 2017 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: 1
soy isoflavones
Dietary Supplement: isoflavones
soy isoflavones: Each tablet contains 246 mg Novasoy, 676 mg calcium, 15 mg riboflavin, and other innert materials to a total weight of 1000 mg. Subject takes two isoflavone tablets plus 1 multi-vitamin per day for five days per week for upto 2 years.
Other Name: Isoflavone pill
Placebo Comparator: 2
carbohydrates (maltodextrin)
Dietary Supplement: carbohydrate
carbohydrate: 246 mg maltodextrin, 676 mg calcium, 15 mg riboflavin and other innert ingredients to a total weight of 1000 mg per tablet. subject takes two tablets plus one multivitamin per day for five days per week for upto 2 years.
Other Name: Sugar pill

Detailed Description:
This is a randomized, double-blind study, with two arms and 100 women in each arm. Premenopausal women will be recruited and randomly allocated to take one of the two different dietary supplements in pills daily for 2 years. The two supplements are soy isoflavones (treatment) and placebo (carbohydrates). Both treatment and placebo pills will contain multi-vitamins and minerals. Multiple blood, urine, and breast fluid samples will be obtained before and during the dietary supplement periods and analyzed for biomarkers of breast cancer risk. At baseline and after the intervention period, breast density and bone density will be assessed by radiologic techniques. The efficacy of the dietary intervention will be determined by comparing mean changes of serum markers for breast cancer risk,dense breast tissue, and bone mineral density over the two year dietary intervention period in the two supplement groups with adjustment for baseline values and individual patient characteristics of interest. We predict that 2 years of soy isoflavone supplement will reduce breast density, which may be explained by individual changes in serum markers of breast cancer risk.

Ages Eligible for Study:   30 Years to 42 Years   (Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • healthy premenopausal women
  • 30 to 42 years old
  • normal mammograms
  • regular menstrual cycles

Exclusion Criteria:

  • abnormal mammograms
  • first degree relatives with breast cancer
  • pregnant or lactating
  • peri- or post-menopause
  • breast augmentation, reduction or lifting
  • on oral contraceptive medications or exogenous hormones
  • medically prescribed diets
  • allergic reaction to soy products
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Please refer to this study by its identifier: NCT00204490

United States, Texas
General Clinical Reserach Center, The University of Texas Medical Branch
Galveston, Texas, United States, 77555-0264
Sponsors and Collaborators
The University of Texas Medical Branch, Galveston
National Cancer Institute (NCI)
National Center for Research Resources (NCRR)
Principal Investigator: Lee-Jane W Lu, Ph.D. The University of Teas Medical Branch
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: The University of Texas Medical Branch, Galveston Identifier: NCT00204490     History of Changes
Other Study ID Numbers: 03-260
UTMB GCRC #635 ( Other Identifier: UTMB ITSCRC )
R01CA095545 ( US NIH Grant/Contract Award Number )
M01RR000073 ( US NIH Grant/Contract Award Number )
1UL1RR029876-01 ( US NIH Grant/Contract Award Number )
Study First Received: September 12, 2005
Last Updated: May 10, 2016

Keywords provided by The University of Texas Medical Branch, Galveston:
mammographic density
bone density

Additional relevant MeSH terms:
Breast Neoplasms
Neoplasms by Site
Breast Diseases
Skin Diseases processed this record on May 25, 2017