title: Cumulative doses of radioiodine in the treatment of differentiated thyroid carcinoma: knowing when to stop.
abstract: OBJECTIVE
  Evaluate the efficacy of cumulative doses (CDs) of 131I-iodide therapy (RIT) in differentiated thyroid cancer (DTC).
  
  
  METHODS
  The probability of progressive disease according to CDs was evaluated in patients < 45 years old and > 45 years old and correlated to tumor-node-metastasis (TNM), thyroglobulin values, histological types and variants, age, and zduration of the disease.
  
  
  RESULTS
  At the end of a follow-up period of 69 ± 56 months, 85 out of 150 DTC patients submitted to fixed doses RIT had no evidence of disease, 47 had stable disease and 18 had progressive disease. Higher CDs were used in the more aggressive variants (p < 0.0001), higher TNM stages (p < 0.0001), and follicular carcinomas (p = 0.0034). Probability of disease progression was higher with CDs > 600 mCi in patients > 45 years old and with CDs > 800 mCi in patients < 45 years.
  
  
  CONCLUSIONS
  Although some patients may still respond to high CDs, the impact of further RIT should be carefully evaluated and other treatment strategies may be warranted.
authors.affiliation: Division of Nuclear Medicine, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, São Paulo, SP, Brazil.
authors.forename: Raul
authors.initials: R
authors.lastname: Martins-Filho
authors.forename: Laura S
authors.initials: LS
authors.lastname: Ward
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Amorim
authors.forename: Allan O
authors.initials: AO
authors.lastname: Santos
authors.forename: Mariana C L de
authors.initials: MC
authors.lastname: Lima
authors.forename: Celso D
authors.initials: CD
authors.lastname: Ramos
authors.forename: Patricia S
authors.initials: PS
authors.lastname: Matos
authors.forename: Lígia V M
authors.initials: LV
authors.lastname: Assumpção
authors.forename: Edwaldo E
authors.initials: EE
authors.lastname: Camargo
authors.forename: Elba C S C
authors.initials: EC
authors.lastname: Etchebehere
mesh_terms: D002291:Carcinoma, Papillary / Q000378:metabolism / Q000532:radiotherapy* / Q000556:secondary; D018450:Disease Progression; D004307:Dose-Response Relationship, Radiation; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000008:administration & dosage* / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D013964:Thyroid Neoplasms / Q000532:radiotherapy*; D016896:Treatment Outcome
chemical_list: D007457:Iodine Radioisotopes