Role of Soy Supplementation in Prostate Cancer Development

Phase 3

Completed

Brief Summary: This is a randomized study evaluating the effectiveness and direct effect a commercial soy supplement has on prostate cancer and normal prostate tissue. Patient will be randomized it either receive placebo or a commercial soy supplement for 2-4 weeks prior to the planned surgery for treatment of their prostate cancer. Patient's blood and prostate tissue will be evaluated to determine the effects of the soy supplement on the prostate tissue.

Detailed Description: This is a randomized study evaluating the effectiveness and direct effect a commercial soy supplement has on prostate cancer and normal prostate tissue. Patients will be randomized to either receive placebo or a commercial soy supplement for 2-4 weeks prior to the planned surgery for treatment of their prostate cancer. The specific objectives are:

1. To assess the effect of soy supplementation on endogenous hormone production levels and serum prostate specific antigens.

2. To assess the impact of soy supplementation on estrogen receptor expression(ER).

3. To determine the impact of soy isoflavones on cell cycle regulation and associated gene expression.

Recruitment & Eligibility

Inclusion Criteria

Histologically proven prostate cancer.
Surgical candidate for prostatectomy.
During study period, must agree not to take new supplements.
No concurrent chemotherapy, radiation or hormonal therapy.
No history of prior allergy to soy based products.
Must not have been taking soy supplements or soy isoflavones within 90 days prior to study enrollment.
Must be able to safely be on study supplements for period of at least two weeks prior to scheduled prostatectomy.
Must give written and informed consent in accordance with institutional and federal guidelines.

Exclusion Criteria

During study period, must agree not to take new supplements.

No concurrent chemotherapy, radiation or hormonal therapy.
No history of prior allergy to soy based products.
Must not have been taking soy supplements or soy isoflavones within 90 days prior to study enrollment.
Must be able to safely be on study supplements for period of at least two weeks prior to scheduled

Arm && Interventions

Group	Intervention	Description
Arm Placebo	Placebo	Placebo
Arm Soy Supplement	Soy Supplement	Soy Supplement

Primary Outcome Measures

Name	Time	Method
Effect of Soy Isoflavones on Serum Testosterone Levels.	Two weeks	Total testosterone (ng/ml) serum levels were measured at the time of enrollment(baseline), after two weeks on soy supplement(time point 1), and just prior to prostatectomy (time point 2). All patients must have completed at least two week of soy supplement or placebo and time point 3 varied depending on date of planned prostatectomy. Results were analyzed and are reported at the two week time period, comparing between patients receiving soy supplement or placebo.

Secondary Outcome Measures

Name	Time	Method
Effect of Soy Isoflavones on Estrogen Receptor Status	Two weeks	Samples of the prostate cancer tissue (paraffin embedded) were sectioned and placed on a glass slide. Using immunohistochemistry and an estrogen receptor antibody, sections were stained and assess to determine the extent of estrogen receptor expression. Patients in the soy supplement arm's samples results were compared to placebo arm results.
Molecular Effects of Soy Supplementation Compared to Placebo.	One year	Using a tissue microarray targeting the cell cycle, selected fresh prostate cancer samples were evaluated in patients in the soy supplement arm compared to the placebo arm.