Soy Isoflavones in Treating Patients Who Are Undergoing Radical Prostatectomy for Stage I or Stage II Adenocarcinoma of the Prostate

Overview

RATIONALE: Chemoprevention therapy is the use of certain drugs to try to prevent or delay the development of early cancer. Soy isoflavones may be effective in delaying the development of early prostate cancer. PURPOSE: This randomized phase II trial is studying different regimens of soy isoflavones to compare how well they work in treating patients who are undergoing radical prostatectomy for stage I or stage II prostate cancer (adenocarcinoma).

OBJECTIVES: * Compare blood/prostate biomarkers of oxidative stress and prostate cancer risk in patients with stage I or II adenocarcinoma of the prostate treated with 3 different dose levels of soy isoflavones before radical prostatectomy. * Compare prostatic tissue biomarkers of proliferation and apoptosis in patients treated with these regimens. * Determine the potential response, in terms of tumor and prostatic intraepithelial neoplasia grade and volume, extraprostatic extension, and serum prostate-specific antigen level, in patients treated with soy isoflavones and in those treated with placebo. * Determine the safety of soy isoflavone supplementation in these patients. OUTLINE: This is a randomized, double-blind, placebo-controlled, parallel-group study. Patients are stratified according to tumor stage (T1c vs T2). Patients are randomized to 1 of 4 treatment arms. * Arm I (control group): Patients receive oral placebo once daily. * Arm II: Patients receive oral soy isoflavones and oral placebo once daily. * Arm III: Patients receive a higher dose of oral soy isoflavones and oral placebo once daily. * Arm IV: Patients receive a higher dose (higher than arm III) of oral soy isoflavones once daily. In all arms, treatment continues for 2-6 weeks (depending on the time from study entry to planned surgery) in the absence of unacceptable toxicity. All patients then undergo radical prostatectomy. Patients are followed at 1 week. PROJECTED ACCRUAL: A total of 100 patients (25 per treatment arm) will be accrued for this study within 12.5 months.

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Eligibility

Locations (1)

Outcomes