title: Vitamin D and cancer: does it really matter?
abstract: OBJECTIVE
  This article provides a background for an evidence-based decision regarding the prescription of vitamin D for cancer prevention and improvement of outcomes in oncology.
  
  
  RESULTS
  In 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.
  
  
  CONCLUSIONS
  Vitamin 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.
authors.affiliation: aInstituto do Câncer do Estado de São Paulo bHospital Sírio Libanês, Sao Paulo, Brazil.
authors.forename: Mariana
authors.initials: M
authors.lastname: Scaranti
authors.forename: Gilberto de Castro
authors.initials: Gde C
authors.lastname: Júnior
authors.forename: Ana Oliveira
authors.initials: AO
authors.lastname: Hoff
mesh_terms: D017326:Clinical Trials, Phase III as Topic; D006801:Humans; D009369:Neoplasms / Q000188:drug therapy / Q000517:prevention & control / Q000628:therapy*; D016032:Randomized Controlled Trials as Topic; D014807:Vitamin D / Q000627:therapeutic use*
chemical_list: D014807:Vitamin D