Vitamin D and cancer: does it really matter?

Purpose of reviewThis article provides a background for an evidence-based decision regarding the prescription of vitamin D for cancer prevention and improvement of outcomes in oncology.Recent findingsIn 2014, Feldman and colleagues published a review suggesting a beneficial role for vitamin D in cancer development. In the same year, a Cochrane meta-analysis that included 18 randomized clinical trials comparing vitamin D administration versus no intervention in healthy population found no difference regarding cancer incidence between the groups. One year later, a phase III trial published in the New England Journal of Medicine did not show any protective effect of vitamin D against adenoma development.SummaryVitamin D is well known for its importance in calcium and phosphate homeostasis, being essential for bone mineralization. However, calcitriol, or 1,25-dyhydroxy-vitamin D3, is a multifunctional steroid hormone with many extra skeletal actions and may regulate signaling pathways related to cancer development and progression. In preclinical studies, it was shown that vitamin D can promote cell differentiation and inhibit proliferation, angiogenesis, and cell migration. Inconsistent results are found in epidemiological studies and early trials regarding clinical effects of vitamin D supplementation and cancer in terms of prevention and impact in cancer-related mortality.