 After completion of course 2 week 16, patients undergo biopsy. Patients continue to receive calcitriol for up to 3 additional weeks while the biopsy is being evaluated. Patients with persistent high-grade prostatic intraepithelial neoplasia HGPIN by biopsy receive 2 additional courses of calcitriol. Patients with no HGPIN or prostate cancer by biopsy are removed from the study. 