Decreased incidence of prostate cancer with selenium supplementation: results of a double-blind cancer prevention trial.

Objective: To test if supplemental dietary selenium is associated with changes in the incidence of prostate cancer.

Patients And Method: A total of 974 men with a history of either a basal cell or squamous cell carcinoma were randomized to either a daily supplement of 200 microg of selenium or a placebo. Patients were treated for a mean of 4.