title: Recombinant human thyroid stimulating hormone in thyroid remnant ablation with 1.1 GBq 131iodine in low-risk patients.
abstract: OBJECTIVE
  To evaluate the efficacy of recombinant human thyroid stimulating hormone [rhTSH (versus hypothyroidism)] in thyroid ablation with an activity of 1.1 GBq (30 mCi) (131)I.
  
  
  METHODS
  A total of 102 patients with thyroid cancer who fulfilled the following criteria were studied: submitted to total thyroidectomy with complete tumor resection; tumor ≤4 cm without extrathyroid invasion or lymph node metastases; negative anti-thyroglobulin (anti-Tg) antibodies. Thirty-two patients (group A) received 0.9 mg of rhTSH for 2 consecutive days followed by (131)I administration and 70 patients (group B) were prepared by levothyroxine withdrawal for 4 weeks. The groups were similar in sex, age, and tumor characteristics.
  
  
  RESULTS
  Ablation was successful (stimulated Tg<1 ng/mL and negative diagnostic whole-body scanning and neck ultrasonography 9 to 12 mo after ablation) in 27 patients of group A (84.3%) and in 58 of group B (83%). Considering patients with Tg greater than 1 ng/mL immediately before (131)I administration, the rates were 72.2% in group A and 75% in group B. In group A, the ablation rate was similar for patients who discontinued levothyroxine-T4 3 days before (131)I administration and those maintained on hormone therapy. The mean follow-up was 29.6 months in group A and 55 months in group B. Stimulated Tg (after rhTSH) was undetectable in 29 patients of group A (90.6%) and in 61 of group B (87%) and 1 patient of group B presented cervical metastases at the last assessment.
  
  
  CONCLUSIONS
  Low (131)I activity after rhTSH is effective for remnant ablation in patients who are at low risk of recurrence.
authors.affiliation: Thyroid Department, Endocrinology Service, Santa Casa de Belo Horizonte, Minas Gerais, Brazil. pedrorosario@globo.com
authors.forename: Pedro Weslley
authors.initials: PW
authors.lastname: Rosario
authors.forename: Arthur Cezar Malard
authors.initials: AC
authors.lastname: Xavier
mesh_terms: D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood; D044963:Biopsy, Fine-Needle; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007037:Hypothyroidism / Q000209:etiology / Q000517:prevention & control*; D007457:Iodine Radioisotopes / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000601:surgery*; D013965:Thyroidectomy; D057073:Thyrotropin Alfa / Q000627:therapeutic use*; D013974:Thyroxine / Q000008:administration & dosage*; D013997:Time Factors; D016896:Treatment Outcome; D014463:Ultrasonography
chemical_list: D001323:Autoantibodies; D007457:Iodine Radioisotopes; D057073:Thyrotropin Alfa; C006606:anti-thyroglobulin; D013974:Thyroxine