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

RATIONALE: Chemoprevention therapy is the use of certain drugs to try to prevent the development of cancer. The use of selenium may be an effective way to prevent prostate cancer in patients who have neoplasia of the prostate.

PURPOSE: Randomized phase III trial to study the effectiveness of selenium in preventing prostate cancer in patients who have 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.

Eligibility Criteria:
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