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

This study has been completed.
Sponsor:
Information provided by:
National Center for Complementary and Alternative Medicine (NCCAM)
ClinicalTrials.gov Identifier:
NCT00200824
First received: September 13, 2005
Last updated: March 10, 2009
Last verified: August 2006
  Purpose

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.


Condition Intervention Phase
Breast Cancer
Prostate Cancer
Drug: Soy Isoflavone Nutritional Supplements
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Crossover Assignment
Masking: Double-Blind
Primary Purpose: Prevention
Official Title: Effects of Soy Isoflavones on the Prostate, Breast and Bone

Resource links provided by NLM:


Further study details as provided by National Center for Complementary and Alternative Medicine (NCCAM):

Primary Outcome Measures:
  • Markers of Bone Density
  • Basic Science (e.g., proliferation of cancer cells in vitro)

Secondary Outcome Measures:
  • Bioavailability

Study Start Date: May 2000
Estimated Study Completion Date: January 2005
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.

  Eligibility

Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

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
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00200824

Locations
United States, California
Christopher Gardner
Stanford, California, United States, 94305-5705
Sponsors and Collaborators
Investigators
Principal Investigator: Christopher Gardner Stanford University
  More Information

Additional Information:
No publications provided

ClinicalTrials.gov Identifier: NCT00200824     History of Changes
Other Study ID Numbers: R01 AT000486
Study First Received: September 13, 2005
Last Updated: March 10, 2009
Health Authority: United States: Federal Government

Keywords provided by National Center for Complementary and Alternative Medicine (NCCAM):
isoflavones
soy
postmenopausal
men
prostate
breast
bone

Additional relevant MeSH terms:
Breast Neoplasms
Prostatic Neoplasms
Neoplasms by Site
Neoplasms
Breast Diseases
Skin Diseases
Genital Neoplasms, Male
Urogenital Neoplasms
Genital Diseases, Male
Prostatic Diseases

ClinicalTrials.gov processed this record on July 31, 2014