Trial Information

Vitamin D Supplementation in Veterans With Early-Stage Prostate Cancer

Vitamin D promotes the differentiation of prostate cancer (PCa) cells, maintains the
differentiated phenotype of prostate epithelial cells, and can induce prostate cancer cell
death, raising the possibility that vitamin D deficiency over time promotes the progression
of subclinical PCa to clinical disease. These considerations support the use of vitamin D3
as a chemopreventive agent.

We hypothesize that a daily dose of vitamin D3 (4,000 IU) taken for one year by Veterans
diagnosed with low-risk, early-stage PCa, who are eligible for active surveillance will: a)
result in a measurable decrease of serum PSA levels in a significant number of enrolled
subjects, and b) be associated with a stabilization or improvement of their PCa pathology,
as assessed through histological examination of prostate tissue biopsy specimens (Gleason
score and percent of positive biopsies) obtained at the end of the study, as part of their
standard medical care for active surveillance.

This VA Merit application proposes to conduct a randomized, placebo-controlled clinical
study aimed at measuring the efficacy of vitamin D3 (4000IU/day) supplementation in Veterans
diagnosed with early-stage prostate cancer, who elect to have their disease monitored
through active surveillance (before considering definitive therapy). The main objectives of
this proposed clinical study are as follows:

1. To determine whether a daily supplement of 4,000 IU of vitamin D3 taken for twelve
months will result in a measurable and significant decrease of serum PSA levels in
Veterans diagnosed with low-risk, early stage PCa (Gleason score 6, PSA 10, clinical
stage T1C or T2a), who elect to have their disease monitored through active
surveillance for at least one year.

2. To determine in enrolled Veterans the pathology status of their PCa by analyzing
prostate tissue biopsy specimens at the end of the study (Gleason score and percentage
of positive biopsies), and by comparing them with those obtained before enrollment in
this study, as part of their standard medical care.

The implementation of these proposed studies will allow us to assess whether vitamin D3
supplementation can be utilized as a chemopreventive regimen in Veterans diagnosed with
low-risk, early stage PCa, and provide a useful addition to active surveillance.