This is a report of research efforts underway at the Arizona
Cancer Center. These efforts build upon Larry Clark's unanticipated clinical prevention trial results: those results indicated that 200 microg/day of
selenium in selenized yeast decreased
prostate cancer risk by almost 60%. The trials underway address various phases of the possible preventive activity of
selenium. The first of these, for men who are suspected to have
prostate cancer but who have had a biopsy revealing no evidence of
cancer, will test the ability of
selenium to prevent the development of clinical
prostate cancer. The second is for men with high-grade
prostatic intraepithelial neoplasia; the trial will test whether
selenium will prevent the development of
prostatic cancer in this high-risk group. The third trial is for men who have been diagnosed with
prostate cancer and are scheduled for
prostatectomy: the trial is designed to test whether evidence of
selenium-linked changes can be identified in the tissue removed at
prostatectomy. The fourth trial is for men who have been diagnosed with
prostate cancer but who have chosen neither surgery nor irradiation; this trial will evaluate whether treatment with
selenium will inhibit the progress of
prostate cancer. Together, these trials will provide important information as to the
prostate cancer chemopreventive potential of
selenium.