title: Is thyroid stunning clinically relevant? A retrospective analysis of 208 patients.
abstract: OBJECTIVE
  Current guidelines have advised against the performance of (131)I-iodide diagnostic whole body scintigraphy (dxWBS) to minimize the occurrence of stunning, and to guarantee the efficiency of radioiodine therapy (RIT). The aim of the study was to evaluate the impact of stunning on the efficacy of RIT and disease outcome.
  
  
  METHODS
  This retrospective analysis included 208 patients with differentiated thyroid cancer managed according to a same protocol and followed up for 12-159 months (mean 30 ± 69 months). Patients received RIT in doses ranging from 3,700 to 11,100 MBq (100 mCi to 300 mCi). Post-RIT-whole body scintigraphy images were performed 10 days after RIT in all patients. In addition, images were also performed 24-48 hours after therapy in 22 patients. Outcome was classified as no evidence of disease (NED), stable disease (SD) and progressive disease (PD).
  
  
  RESULTS
  Thyroid stunning occurred in 40 patients (19.2%), including 26 patients with NED and 14 patients with SD. A multivariate analysis showed no association between disease outcome and the occurrence of stunning (p = 0.3476).
  
  
  CONCLUSIONS
  The efficacy of RIT and disease outcome do not seem to be related to thyroid stunning.
authors.affiliation: Division of Nuclear Medicine of the Department of Radiology, School of Medical Sciences, Universidade Estadual de Campinas, Campinas, SP, Brazil.
authors.forename: Elba C S C
authors.initials: EC
authors.lastname: Etchebehere
authors.affiliation: Division of Nuclear Medicine of the Department of Radiology, School of Medical Sciences, Universidade Estadual de Campinas, Campinas, SP, Brazil.
authors.forename: Allan O
authors.initials: AO
authors.lastname: Santos
authors.affiliation: Department of Pathology, School of Medical Sciences, Unicamp, Campinas, SP, Brazil.
authors.forename: Patrícia S
authors.initials: PS
authors.lastname: Matos
authors.affiliation: Division of Endocrinology of the Department of Internal Medicine, School of Medical Sciences, Unicamp, Campinas, SP, Brazil.
authors.forename: Lígia V M
authors.initials: LV
authors.lastname: Assumpção
authors.affiliation: Division of Nuclear Medicine of the Department of Radiology, School of Medical Sciences, Universidade Estadual de Campinas, Campinas, SP, Brazil.
authors.forename: Maria Cecília V L
authors.initials: MC
authors.lastname: Lima
authors.affiliation: Division of Nuclear Medicine of the Department of Radiology, School of Medical Sciences, Universidade Estadual de Campinas, Campinas, SP, Brazil.
authors.forename: Mariana C L
authors.initials: MC
authors.lastname: Lima
authors.affiliation: Laboratory of Molecular Cancer Genetics, School of Medical Sciences, Unicamp, Campinas, SP, Brazil.
authors.forename: Laura S
authors.initials: LS
authors.lastname: Ward
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000532:radiotherapy*; D000328:Adult; D002291:Carcinoma, Papillary / Q000532:radiotherapy*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D013961:Thyroid Gland / Q000000981:diagnostic imaging* / Q000601:surgery; D013964:Thyroid Neoplasms / Q000145:classification / Q000532:radiotherapy*; D013965:Thyroidectomy; D016896:Treatment Outcome; D051598:Whole Body Imaging
chemical_list: D007457:Iodine Radioisotopes