A Double-Blind, Placebo-Controlled, Randomized Study Of Combination Vitamin E, Selenium And Soy Protein Product In Subjects With High Grade Prostatic Intraepithelial Neoplasia

OBJECTIVES:

• Determine whether nutritional supplementation with soy protein isolate, vitamin E, and selenium can delay the time to development of invasive prostate cancer (disease-free survival) in patients with high-grade prostatic intraepithelial neoplasia.
• Determine the effect of this supplementation on intermediate endpoints that may reflect a lessened risk of invasive prostate cancer (e.g., serum PSA levels, hormone levels, lycopene, malondialdehyde, vitamin E, and reduced thiol groups) in these patients.
• Determine the safety of this supplementation in these patients.

OUTLINE: This is a randomized, double-blind, multicenter study. Patients are stratified according to participating center. Patients are randomized to 1 of 2 treatment arms.

• Arm I: Patients receive oral vitamin E, oral selenium, and oral soy protein isolate twice daily.
• Arm II: Patients receive oral placebo twice daily. In both arms, treatment continues for 3 years in the absence of invasive prostate cancer (demonstrated on biopsy) or unacceptable toxicity.

Patients are followed every 3 months for 1 year and then every 6 months for 2 years.