Effects of Soy Compounds on Breast Cancer, Prostate Cancer, and Bone Health

March 10, 2009 updated by: National Center for Complementary and Integrative Health (NCCIH)

Effects of Soy Isoflavones on the Prostate, Breast and Bone

This study will determine the effects of soy products on in vitro surrogate cancer markers as well as bone density markers and quality of life parameters in men and women. This study will also determine concentrations of isoflavones (naturally occurring plant compounds that act like estrogen in the body) in prostate tissue that has been removed during prostatectomy, as well as in the blood.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

In the United States, consumption of soy products has dramatically increased in the past several years. Foods made from soy are high in isoflavones and evidence suggests that these isoflavones, genistein in particular, have many beneficial properties such as alleviating menopausal side effects and reducing the risk of osteoporosis, breast cancer, and prostate cancer. However, this data has been derived largely from studies with animal or cell models; human trials are limited. This study will determine the effects of soy isoflavones on quality of life and cancer and bone density markers.

While isoflavones have been purported to inhibit the proliferation of cancer cells, the concentrations required for this anti-cancer effect were determined to be much higher than the concentrations that can be achieved in plasma after intake of isoflavones. Recent animal studies have suggested that isoflavones may be concentrated 10-fold in tissue compared to blood concentrations. If this is true, then the higher concentration would be in the range found in the cancer cell line research to be protective of cancer. This study will determine whether tissue concentrations are similar to, higher than, or different than blood concentrations.

This study will last 5 years and will comprise three populations: men with prostate cancer on androgen ablation therapy, postmenopausal women on hormone replacement therapy (HRT), and postmenopausal women not on HRT. Participants will be randomly assigned to receive either isoflavone or placebo for two to four weeks. Participants' serum and serum extracts will be incubated with cultured human cell lines (prostate cancer, breast cancer and osteoblasts) and estrogenic and non-estrogenic mechanisms of action investigated. The human sera data will be complemented by parallel studies of direct addition of crystalline isoflavones (genistein, daidzein and equol) to the same cultured human cell lines. Participant's serum and urine also will be tested for markers of bone resorption and formation. Quality of life issues will be assessed with questionnaires.

Study Type

Interventional

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • California
      • Stanford, California, United States, 94305-5705
        • Christopher Gardner

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria

  • Scheduled for prostatectomy
  • Willing and able to consume study tablets for at least 2 weeks prior to surgery
  • Willing to accept random assignment
  • Signed informed consent

Exclusion Criteria

  • Unwilling to avoid soy intake during the study period
  • Currently taking antibiotics

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Markers of Bone Density
Basic Science (e.g., proliferation of cancer cells in vitro)

Secondary Outcome Measures

Outcome Measure
Bioavailability

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Center for Complementary and Integrative Health (NCCIH)

Investigators

  • Principal Investigator: Christopher Gardner, Stanford University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

May 1, 2000

Study Completion

January 1, 2005

Study Registration Dates

First Submitted

September 13, 2005

First Submitted That Met QC Criteria

September 13, 2005

First Posted (Estimate)

September 20, 2005

Study Record Updates

Last Update Posted (Estimate)

March 12, 2009

Last Update Submitted That Met QC Criteria

March 10, 2009

Last Verified

August 1, 2006

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • R01AT000486 (U.S. NIH Grant/Contract)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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