S9917, Selenium in Preventing Cancer in Patients With Neoplasia of the Prostate

OBJECTIVES:

• Compare the effects of selenium versus placebo on the 3-year incidence rate of prostate cancer in patients with high-grade prostatic intraepithelial neoplasia.
• Compare the toxicity of these regimens in these patients.
• Compare the effects of these regimens on the rate of increase in prostate-specific antigen (PSA) in these patients.
• Compare the effects of these regimens on prostatic cellular proliferation and apoptosis, degradation of basal cell integrity of prostatic ducts, and changes in nuclear chromatin patterns in these patients.

OUTLINE: This is a randomized, double-blind, placebo-controlled, multicenter study. Patients are stratified according to age (40-60 vs 61 and over), race (African American vs other), baseline PSA (less than 4 ng/mL vs 4-10 ng/mL), concurrent vitamin E supplementation (yes vs no), and cores obtained from initial biopsy (10 or more vs less than 10). Patients are randomized to 1 of 2 arms.

• Arm I: Patients receive oral selenium once daily.
• Arm II: Patients receive oral placebo once daily. Treatment in both arms continues for 3 years in the absence of progression to prostate cancer or unacceptable toxicity.

Patients are followed every 6 months for 2 years and then annually for 8 years.

PROJECTED ACCRUAL: A total of 465 patients will be randomized for this study.

DISEASE CHARACTERISTICS:

• Diagnosis of high-grade prostatic intraepithelial neoplasia with no evidence of cancer

• Documented by a digital rectal exam and biopsy of the prostate with transrectal ultrasound guidance (required if fewer than 6 cores obtained in biopsy) meeting one of the following conditions:

• Biopsy yielded fewer than 10 cores within the past 24 months OR yielded more than 10 cores 6-24 months before study
• Biopsy yielded 10 or more cores within the past 6 months
• PSA ≤ 10 ng/mL (≤ 5 ng/mL for patients who have received finasteride or other androgen suppressor within the past 2 months)
• American Urological Association symptom score of less than 20

PATIENT CHARACTERISTICS:

Age:

• 40 and over

Performance status:

• SWOG 0-1

Life expectancy:

• Not specified

Hematopoietic:

• Not specified

Hepatic:

• Not specified

Renal:

• Not specified

Other:

• No malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer or adequately treated stage I or II cancer that is in complete remission

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• Not specified

Endocrine therapy

• See Disease Characteristics
• No concurrent finasteride or any other androgen suppressor

Radiotherapy

• Not specified

Surgery

• Not specified

Other

• At least 30 days since prior daily dietary supplements containing 50 micrograms or more of selenium
• No concurrent daily dietary supplements containing more than 50 micrograms of selenium