title: Vitamin D Deficiency Is Associated With the Severity of Radiation-Induced Proctitis in Cancer Patients.
abstract: OBJECTIVE
  Radiation-induced injury to normal tissues is a common complication of radiation therapy in cancer patients. Considering the role of vitamin D in mucosal barrier hemostasis and inflammatory responses, we investigated whether vitamin D deficiency is associated with the severity of radiation-induced acute proctitis in cancer patients.
  
  
  METHODS
  This prospective observational study was conducted in cancer patients referred for pelvic radiation therapy. Serum concentration of 25-hydroxyvitamin D was measured before radiation therapy. Vitamin D deficiency was defined as 25-hydroxyvitamin D concentrations of <35 nmol/L and <40 nmol/L in male and female patients, respectively, based on available normative data. Acute proctitis was assessed after 5 weeks of radiation therapy (total received radiation dose of 50 Gy) and graded from 0 to 4 using Radiation Therapy Oncology Group (RTOG) criteria.
  
  
  RESULTS
  Ninety-eight patients (57.1% male) with a mean age of 62.8 ± 9.1 years were studied. Vitamin D deficiency was found in 57 patients (58.1%). Symptoms of acute proctitis occurred in 72 patients (73.4%) after radiation therapy. RTOG grade was significantly higher in patients with vitamin D deficiency than in normal cases (median [interquartile range] of 2 [0.5-3] vs 1 [0-2], P=.037). Vitamin D deficiency was associated with RTOG grade of ≥2, independent of possible confounding factors; odds ratio (95% confidence interval) = 3.07 (1.27-7.50), P=.013.
  
  
  CONCLUSIONS
  Vitamin D deficiency is associated with increased severity of radiation-induced acute proctitis. Investigating the underlying mechanisms of this association and evaluating the effectiveness of vitamin D therapy in preventing radiation-induced acute proctitis is warranted.
authors.affiliation: Medical Student's Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Amir
authors.initials: A
authors.lastname: Ghorbanzadeh-Moghaddam
authors.affiliation: Medical Student's Research Center, Isfahan University of Medical Sciences, Isfahan, Iran; Poursina Hakim Research Institution, Isfahan, Iran. Electronic address: Gholamrezaei@med.mui.ac.ir.
authors.forename: Ali
authors.initials: A
authors.lastname: Gholamrezaei
authors.affiliation: Department of Radiotherapy Oncology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Simin
authors.initials: S
authors.lastname: Hemati
mesh_terms: D000208:Acute Disease; D000368:Aged; D005260:Female; D005833:Genital Neoplasms, Female / Q000097:blood / Q000532:radiotherapy*; D006801:Humans; D007413:Intestinal Mucosa / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D011349:Proctitis / Q000209:etiology*; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000097:blood / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000150:complications*; D001749:Urinary Bladder Neoplasms / Q000097:blood / Q000532:radiotherapy*; D014807:Vitamin D / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications*
chemical_list: D014807:Vitamin D