Vitamin D3 Supplementation for Low-Risk Prostate Cancer: A Randomized Trial

Vitamin D promotes the differentiation of prostate cancer cells and maintains the differentiated phenotype of prostate epithelial cells. The results of the investigators' clinical studies indicate that vitamin 1,25 dihydroxyvitamin D3 (VD3) supplementation results in a decrease of positive cancer cores at repeat biopsy in subjects with low-risk prostate cancer. The investigators hypothesize that Veterans who have early-stage prostate cancer and who take vitamin D3 at 4000 international units per day (intervention group) will show an improvement in the number of positive cores and in Gleason score at repeat biopsy, and a decreased likelihood of undergoing definitive treatment (prostatectomy or radiation therapy), compared to Veteran subjects taking placebo (control group).