Vitamin D shows significant potential as a
therapy for
prostate cancer. However, its use in clinical trials has been hampered by its induction of
hypercalcemia at serum concentrations required to suppress
cancer cell proliferation. This has spurred the development of less calcemic analogs of
vitamin D. In this article, we review the clinical trials and consider the future directions of the use of
vitamin D and its analogs in the treatment or
chemoprevention of
prostate cancer. First, we summarize the epidemiological evidence leading to the hypothesis that
vitamin D has anticancer activity. We then review the clinical trials using
vitamin D analogs that involve patients with
prostate cancer and conclude with a brief overview of our planned study with
vitamin D5, [
1alpha(OH)D5], which will begin shortly. Data for this review were identified by searches of PubMed, the Cochrane Library, Biosis, and references from relevant articles, using the search terms "
vitamin D," "
prostate cancer," "
chemoprevention" and "
vitamin D analog." Abstracts from recent international meetings were also reviewed but were only included when they were the only known reference to the clinical trial or the research mentioned. Only papers published in English were included.