Selenium in Treating Patients With Prostate Cancer

OBJECTIVES:

• To investigate the ability of selenium to prevent progression in patients with adenocarcinoma of the prostate.
• To investigate the ability of selenium to effectively modulate biomarkers of prostate cancer.
• To determine if selenium modifies the progression of prostate cancer based on an analysis of initial biopsy, subsequent blood biomarkers, and urological symptoms.
• To further establish the safety of chronic supplementation with selenium in these patients.

OUTLINE: Patients are stratified according to Gleason score (low vs moderate). Patients are randomized to 1 of 3 treatment arms.

• Arm I: Patients receive oral placebo once daily for 48 months in the absence of disease progression or unacceptable toxicity.
• Arm II: Patients receive low-dose oral selenium once daily for 48 months in the absence of disease progression or unacceptable toxicity.
• Arm III: Patients receive high-dose oral selenium once daily for 48 months in the absence of disease progression or unacceptable toxicity.

Blood and tissue samples are collected periodically for biomarker laboratory studies. Blood samples are analyzed for levels of prostate-specific antigen, chromogranin A, alkaline phosphatase, alpha tocopherol, lycopene, and other vitamins; levels of selenium by atomic absorption spectrometry; and oxidative damage to DNA. Tissue samples are analyzed for levels of Bcl-2, p53, Ki-67, thioredoxin reductase, thioredoxin, and glutathione peroxidase by immunohistochemistry and for apoptotic index by TUNEL assay.

Patients complete urological symptom questionnaires and other questionnaires periodically.