title: Predictive factors of failure in a fixed 15 mCi 131I-iodide therapy for Graves' disease.
abstract: OBJECTIVE
  To investigate the factors influencing the success rate in a fixed, 15 mCi approach for treatment of Graves' hyperthyroidism.
  
  
  METHODS
  The thyroid function outcome (hyperthyroidism or euthyroidism/hypothyroidism) was verified at least 1 year after radioiodine therapy (RIT) retrospectively and compared with presenting clinical characteristics and pre-RIT parameters in 87 patients treated with I-iodide for Graves' disease in a tertiary care center.
  
  
  RESULTS
  After RIT, 16 patients (18.4%) became euthyroid, 54 patients (62.1%) became hypothyroid, and 17 (19.5%) remained hyperthyroid. We found no statistically significant association between thyroid function outcome and gender (P = 0.50), ophthalmopathy (P = 0.69), drug used (methimazole or propylthiouracil; P = 1.00), maintenance or withdrawal of thionamides pre-RIT (P = 0.98), or 99mTc sodium pertechnetate thyroid uptake prior to RIT (P = 0.75). The only variable associated with the success rate was thyroid mass <62 g (P < 0.001).
  
  
  CONCLUSIONS
  Our study has shown that a fixed 15 mCi approach for treatment of Graves' disease was effective, but high failure rates were observed in patients presenting larger goiters, particularly those with estimated thyroid mass >62 g.
authors.affiliation: Endocrinology Division, Department of Internal Medicine, Faculty of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil.
authors.forename: Arnaldo
authors.initials: A
authors.lastname: Moura-Neto
authors.forename: Camila
authors.initials: C
authors.lastname: Mosci
authors.forename: Allan O
authors.initials: AO
authors.lastname: Santos
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Amorim
authors.forename: Mariana C L
authors.initials: MC
authors.lastname: de Lima
authors.forename: Elba C S C
authors.initials: EC
authors.lastname: Etchebehere
authors.forename: Marcos Antonio
authors.initials: MA
authors.lastname: Tambascia
authors.forename: Celso Dario
authors.initials: CD
authors.lastname: Ramos
authors.forename: Denise Engelbrecht
authors.initials: DE
authors.lastname: Zantut-Wittmann
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006111:Graves Disease / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009929:Organ Size / Q000528:radiation effects; D012189:Retrospective Studies; D013961:Thyroid Gland / Q000473:pathology / Q000528:radiation effects; D017211:Treatment Failure; D055815:Young Adult
chemical_list: D007457:Iodine Radioisotopes