Phase III Trial of Selenium for Prostate Cancer Prevention

OBJECTIVES:

• To determine whether selenium (Se) supplementation decreases the incidence of prostate cancer.
• To determine whether Se supplementation inhibits the biochemical progression of prostate cancer.

OUTLINE: This is a multicenter study. Patients are randomized to 1 of 3 treatment arms.

• Arm I: Patients receive oral placebo daily. Treatment continues for up to 57 months in the absence of unacceptable toxicity or diagnosis of prostate cancer.
• Arm II: Patients receive 200 μg of oral selenium (Se) as high-Se Baker's yeast daily. Treatment continues for up to 57 months in the absence of unacceptable toxicity or diagnosis of prostate cancer.
• Arm III: Patients receive 400 μg of oral Se as high-Se baker's yeast daily. Treatment continues for up to 57 months in the absence of unacceptable toxicity or diagnosis of prostate cancer.

Blood samples are collected at baseline, at randomization, and then semi-annually for laboratory and other testing. Tissue samples may also be collected for biomarker analysis. Patients complete an initial questionnaire and urological-symptoms questionnaire at baseline, a follow-up questionnaire after randomization (to capture new illness, medications, and toxicity symptoms during the 30-day run-in period; a urological-symptoms questionnaire; a food-frequency questionnaire; and a mood questionnaire). Patients then undergo questionnaires semi-annually, including vital status, tablet compliance, nutrition, mood, new illnesses or medications, and any incidence of cancer or family history of cancer).