The lack of treatment for ''worried well'' patients with highgrade prostatic intraepithelial neoplasia combined with issues of recurrence and hormone resistance in prostate cancer survivors remains a major public health obstacle. The long latency of prostate cancer development provides an ample opportunity to intervene with mechanistically based chemopreventive agents at various stages of disease progression. Our rationale for selenium intervention is based on current mechanistic knowledge derived solely from preclinical investigations. Clearly, there is sufficient scientific support for its entry into current clinical trials, the outcome of which will be highly valuable in assessing whether selenium can be recommended for cancer survivors.