Vitamin E, Selenium, and Soy Protein in Preventing Cancer in Patients With High-Grade Prostate Neoplasia

Inclusion Criteria

• •DISEASE CHARACTERISTICS:
• •Histologically confirmed high-grade prostatic intraepithelial neoplasia (HGPIN)
• •* No evidence of invasive prostate cancer by at least 2 biopsies within the past 18 months
• •* At least 1 biopsy must show evidence of HGPIN within the past 6 months
• •No prior invasive prostate cancer
• •PATIENT CHARACTERISTICS:
• •Age
• •Not specified
• •Performance status
• •Not specified
• •Life expectancy
• •More than 5 years
• •Hematopoietic
• •Platelet count at least 75,000/mm\^3
• •No coagulopathies
• •Hepatic
• •Bilirubin no greater than 2 times upper limit of normal (ULN)
• •PT (INR) no greater than 1.5 times ULN
• •PTT no greater than 1.5 times ULN
• •No hepatic insufficiencies
• •Renal
• •Creatinine no greater than 2 times ULN
• •No renal insufficiencies
• •Other
• •No prior nonmelanoma skin cancer (e.g., squamous cell or basal cell carcinoma)
• •No other malignancy within the past 5 years except superficial bladder cancer
• •No known bowel malabsorption
• •No dietary behavior (e.g., morbid obesity or eating disorders) that would limit adherence to study therapy
• •No major illness, including psychiatric illness, that would preclude study compliance and follow-up
• •PRIOR CONCURRENT THERAPY:
• •Biologic therapy
• •Not specified
• •Chemotherapy
• •Not specified
• •Endocrine therapy
• •More than 3 months since prior androgen therapy
• •More than 3 months since prior hormonal therapy for benign prostatic hyperplasia (e.g., finasteride)
• •No concurrent finasteride
• •No concurrent androgen therapy
• •Radiotherapy
• •More than 2 years since prior radiotherapy to the pelvic region
• •Surgery
• •Not specified
• •Other
• •More than 2 weeks since prior supplemental vitamin E or selenium
• •No other concurrent vitamin E (greater than 100 IU/day), selenium, or soy protein isolate (more than 2 servings/week)
• •No other concurrent treatment for high-grade prostatic intraepithelial neoplasia