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

Brief Summary:
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 or disease Intervention/treatment Phase
Breast Cancer Dietary Supplement: isoflavones Dietary Supplement: carbohydrate Phase 2

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.

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 197 participants
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
Official Title: Mammographic Density and Soy Isoflavones
Actual Study Start Date : April 2004
Estimated Primary Completion Date : December 2018
Estimated Study Completion Date : December 2018

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Breast Cancer

Arm Intervention/treatment
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

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

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

Information from the National Library of Medicine

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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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): 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

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 ( U.S. NIH Grant/Contract )
M01RR000073 ( U.S. NIH Grant/Contract )
1UL1RR029876-01 ( U.S. NIH Grant/Contract )
First Posted: September 20, 2005    Key Record Dates
Last Update Posted: April 10, 2018
Last Verified: April 2018

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