The Effect of Vitamin D Supplementation on Prostate Cancer: A Systematic Review and Meta-Analysis of Clinical Trials

Abstract

Vitamin D has received attention for its potential to disrupt cancer processes. However, its effect in the treatment of prostate cancer is controversial. This study aimed to assess the effect of vitamin D supplementation on patients with prostate cancer. In the present study, PubMed, Scopus, ISI Web of Science, and Google Scholar were searched up to September 2017 for trials that evaluated the effect of vitamin D supplementation on prostate specific antigen (PSA) response, mortality, and its possible side effects in participants with prostate cancer. The DerSimonian and Laird inverse-weighted random-effects model was used to pool the effect estimates. Twenty-two studies (16 before-after and 6 randomized controlled trials) were found and included in the meta-analysis. The analysis of controlled clinical trials revealed that PSA change from baseline [weighted mean difference (WMD)=–1.66 ng/ml, 95% CI: –0.69, 0.36, p=0.543)], PSA response proportion (RP=1.18, 95% CI: 0.97, 1.45, p=0.104) and mortality rate (risk ratio (RR)=1.05, 95% CI: 0.81–1.36; p=0.713) were not significantly different between vitamin D supplementation and placebo groups. Single arm trials revealed that vitamin D supplementation had a modest effect on PSA response proportion: 19% of those enrolled had at least a 50% reduction in PSA by the end of treatment (95% CI: 7% to 31%; p=0.002). Although before-after studies showed that vitamin D increases the PSA response proportion, it does not seem that patients with prostate cancer benefit from high dose vitamin D supplementation and it should not be recommended for the treatment.

Dietary Factors and Supplements Influencing Prostate-Specific Antigen (PSA) Concentrations in Men with Prostate Cancer and Increased Cancer Risk: An Evidence Analysis Review Based on Randomized Controlled Trials

“…Based on the aforementioned trials and the findings of a relevant systematic review by Petrou and associates [ 152 ], most RCTs suggested a lack of efficacy of vitamin D ONS in reducing PSA concentrations among men harboring PCa. These findings were also corroborated by a more recent meta-analysis, indicating a non-significant difference in PSA change, PSA response proportion and mortality rate between men with PCa receiving vitamin D, as compared with those randomized to a placebo [ 153 ].…”

Circulating Vitamin D and Selenium Levels and Outcome in Prostate Cancer Patients: Lessons from the MARTINI-Lifestyle Cohort

“…As to Vit D status, median levels showed seasonal but also regional dependence in line with previous research [7,11,12]. Stratification by median Vit D plasma levels revealed lower values in smokers and overweight patients, which is supported by findings from other studies [7,[13][14][15], but the observed relationship between Vit D, PSA, and selenium plasma levels is less clear [7,16,17]. In contrast to data from select studies, our analysis [18] failed to show significant differences in pathologic outcomes according to circulating levels of Vit D. However, published prospective data on blood Vit D and PCa risk are limited and not comparable with Vit D status prior to RP [7].…”

Vitamin D-Induced Molecular Mechanisms to Potentiate Cancer Therapy and to Reverse Drug-Resistance in Cancer Cells

“…As recently emerged, contradictory data are reported about the effects of vitamin D supplementation in prostate cancer progression [114]. Although calcitriol is used in the management of patients with secondary hyperparathyroidism in renal insufficiency [111], its administration at high doses has been reported in patients with prostate cancer.…”