Soy Supplements 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.

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