title: Radioiodine-induced oxidative stress in patients with differentiated thyroid carcinoma and effect of supplementation with vitamins C and E and selenium (antioxidants).
abstract: OBJECTIVE
  The objective of this study, in addition to confirming that therapy with 131I causes oxidative stress, was to evaluate the effect of supplementation with vitamins C and E and selenium on this phenomenon by measuring plasma 8-epi-PGF2a, a marker of lipid peroxidation.
  
  
  METHODS
  Forty patients with thyroid cancer submitted to thyroidectomy, who received 3.7 GBq 131I after levothyroxine withdrawal, were selected; 20 patients did not receive (control group) and 20 patients received (intervention group) daily supplementation consisting of 2000 mg vitamin C, 1000 mg vitamin E and 400 µg selenium for 21 days before 131I. Plasma 8-epi-PGF2a was measured immediately before and 2 and 7 days after 131I.
  
  
  RESULTS
  A significant increase in plasma 8-epi-PGF2a after 131I was observed in the two groups. The concentrations of 8-epi-PGF2α were significantly higher in the control group before and 2 and 7 days after 131I. The percentage of patients with elevated 8-epi-PGF2α was also significantly higher in the control group before and after 131I. Furthermore, the increase (percent) in 8-epi-PGF2α was significantly greater in the control group (average of 112.3% versus 56.3%). Only two patients (10%) reported side effects during supplementation.
  
  
  CONCLUSIONS
  Ablation with 131I causes oxidative stress which can be minimized by the use of antioxidants.
authors.affiliation: Programa de Pós-Graduação, Santa Casa de Belo Horizonte, Belo Horizonte, MG, Brasil.|Serviço de Endocrinologia, Santa Casa de Belo Horizonte, Belo Horizonte, MG, Brasil.
authors.forename: Pedro Weslley
authors.initials: PW
authors.lastname: Rosário
authors.affiliation: Programa de Pós-Graduação, Santa Casa de Belo Horizonte, Belo Horizonte, MG, Brasil.
authors.forename: Kelly Cristina Siqueira
authors.initials: KC
authors.lastname: Batista
authors.affiliation: Serviço de Endocrinologia, Santa Casa de Belo Horizonte, Belo Horizonte, MG, Brasil.
authors.forename: Maria Regina
authors.initials: MR
authors.lastname: Calsolari
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000975:Antioxidants / Q000627:therapeutic use*; D001205:Ascorbic Acid / Q000627:therapeutic use; D002277:Carcinoma / Q000188:drug therapy / Q000378:metabolism / Q000532:radiotherapy* / Q000601:surgery; D019587:Dietary Supplements; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000097:blood; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects*; D015227:Lipid Peroxidation / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000528:radiation effects*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012643:Selenium / Q000627:therapeutic use; D013964:Thyroid Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000532:radiotherapy* / Q000601:surgery; D013965:Thyroidectomy; D013974:Thyroxine / Q000627:therapeutic use; D013997:Time Factors; D016896:Treatment Outcome; D014810:Vitamin E / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D000975:Antioxidants; D007457:Iodine Radioisotopes; D014810:Vitamin E; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost; D012643:Selenium; D001205:Ascorbic Acid; D013974:Thyroxine