Soy Isoflavones and Breast Cancer Risk Reduction

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00204490
Recruitment Status : Active, not recruiting
First Posted : September 20, 2005
Last Update Posted : April 10, 2018
National Cancer Institute (NCI)
National Center for Research Resources (NCRR)
Information provided by (Responsible Party):
The University of Texas Medical Branch, Galveston

September 12, 2005
September 20, 2005
April 10, 2018
April 2004
December 2018   (Final data collection date for primary outcome measure)
Breast density [ Time Frame: one or two years after dietary supplements ]
Breast density
Complete list of historical versions of study NCT00204490 on Archive Site
bone density [ Time Frame: one or two years after dietary supplement ]
bone density
Not Provided
Not Provided
Soy Isoflavones and Breast Cancer Risk Reduction
Mammographic Density and Soy Isoflavones
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.
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.
Phase 2
Allocation: Randomized
Intervention Model: Parallel Assignment
Intervention Model Description:
One group received soy isoflavones (60 mg daidzein, 60 mg gensitein and 16.6 mg glycitein, all as aglycone equivalent) Another group, carbohydrate filler
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Masking Description:

Research pharmacist dispensed study pills according to a pre-generated randomization list and were blinded to all other aspects of the study protocol.

Subjects, research staff, investigators, and statistician all were blinded to treatment assignment.

Primary Purpose: Prevention
Breast Cancer
  • 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
  • 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
  • Experimental: 1
    soy isoflavones
    Intervention: Dietary Supplement: isoflavones
  • Placebo Comparator: 2
    carbohydrates (maltodextrin)
    Intervention: Dietary Supplement: carbohydrate
Lu LJ, Nishino TK, Johnson RF, Nayeem F, Brunder DG, Ju H, Leonard MH, Grady JJ, Khamapirad T. Comparison of breast tissue measurements using magnetic resonance imaging, digital mammography and a mathematical algorithm. Phys Med Biol. 2012 Nov 7;57(21):6903-27. doi: 10.1088/0031-9155/57/21/6903. Epub 2012 Oct 9.

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
Active, not recruiting
December 2018
December 2018   (Final data collection date for primary outcome measure)

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
Sexes Eligible for Study: Female
30 Years to 42 Years   (Adult)
Contact information is only displayed when the study is recruiting subjects
United States
UTMB GCRC #635 ( Other Identifier: UTMB ITSCRC )
R01CA095545 ( U.S. NIH Grant/Contract )
M01RR000073 ( U.S. NIH Grant/Contract )
1UL1RR029876-01 ( U.S. NIH Grant/Contract )
Not Provided
Not Provided
The University of Texas Medical Branch, Galveston
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
The University of Texas Medical Branch, Galveston
April 2018

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP