Soy Supplements in Treating Patients Undergoing Surgery for Localized Prostate Cancer

Randomized Phase IIb Preprostatectomy Study of Dietary Supplementation With Soy and Biomarkers of Prostate Cancer Risk and Progression

RATIONALE: Dietary supplementation with soy may keep prostate cancer from growing in patients planning to undergo surgery. PURPOSE: This randomized phase II trial is studying a soy supplement to see how well it works compared to a placebo in treating patients undergoing surgery for localized prostate cancer.

OBJECTIVES: Primary Compare the effect of dietary supplementation with soy vs placebo on biomarkers of cell cycle regulation, proliferation, differentiation, apoptosis, and signaling pathways in patients with localized prostate cancer scheduled to undergo radical prostatectomy. Secondary Compare the toxicity and side effects of these regimens in these patients. Compare the dietary patterns of these patients. OUTLINE: This is a prospective, randomized study. Patients are randomized to 1 of 2 treatment arms. Arm I: Patients receive oral soy supplementation daily for 4 weeks. Arm II: Patients receive oral placebo supplementation daily for 4 weeks. Patients undergo radical prostatectomy within 21 days after completion of soy or placebo supplementation. Blood and tissue samples are collected for biomarker analysis using immunohistochemistry.

adenocarcinoma of the prostate, stage I prostate cancer, stage IIB prostate cancer, stage IIA prostate cancer, stage III prostate cancer, stage IV prostate cancer

Patients receive oral soy supplementation daily for 4 weeks. Patients undergo radical prostatectomy within 21 days after completion of soy supplementation.

Patients receive oral placebo supplementation daily for 4 weeks. Patients undergo radical prostatectomy within 21 days after completion of placebo supplementation.

after a 4 week therapy, within 21 days, a Radical Prostatectomy will be performed, and after that ER-β expression will be measured.

DISEASE CHARACTERISTICS: Histologically confirmed adenocarcinoma of the prostate Clinically localized disease Scheduled for radical prostatectomy No evidence of metastatic disease by bone scan or CT scan of the abdomen or pelvis PATIENT CHARACTERISTICS: ECOG performance status 0-2 No evidence of active nephrolithiasis No history of hypercalcemic syndrome PRIOR CONCURRENT THERAPY: No prior treatment for prostate cancer, including radiotherapy, systemic chemotherapy, surgery, or investigational drugs No other concurrent dietary supplementation with soy, cholecalciferol (vitamin D), or fish oil