title: Higher preablative serum thyroid-stimulating hormone level predicts radioiodine ablation effectiveness in patients with differentiated thyroid carcinoma.
abstract: BACKGROUND
  Radioiodine ablation of remnant thyroid tissue is an important adjuvant therapy of differentiated thyroid carcinoma (DTC) after thyroidectomy. Elevated serum thyroid-stimulating hormone (TSH) level is necessary for successful ablation. The optimum level of serum TSH level necessary for successful radioiodine ablation of well-DTC is, however, yet to be defined. We aimed to determine whether higher serum TSH level will result in a better rate of complete ablation of well-DTC using iodine-131 (I) following initial thyroidectomy.
  
  
  METHODS
  A total of 109 patients with differentiated thyroid cancer were divided into four treatment groups on the basis of serum TSH levels. They were followed up from 6 to 12 months after treatment with stimulated serum thyroglobulin level and a diagnostic whole-body scan with radioactive iodine I to determine early response.
  
  
  RESULTS
  Sixty-four patients had papillary thyroid carcinoma, whereas 45 patients had follicular carcinoma. An excellent response was observed in 66.7% of patients with TSH level more than 90 μIU/ml, 72.2% in the group with TSH level of 60-89 μIU/ml, 48.5% when TSH was 30-59 μIU/ml and 26.7% when TSH was less than 30 μIU/ml (P=0.002).
  
  
  CONCLUSIONS
  Higher preablative serum TSH predicts a better rate of ablation in patients with differentiated thyroid cancer treated with I after thyroidectomy.
authors.affiliation: aDepartment of Nuclear Medicine, University of Pretoria and Steve Biko Academic Hospital, Pretoria bDepartment of Nuclear Medicine, University of Kwa-Zulu Natal, Durban, South Africa.
authors.forename: Ismaheel O
authors.initials: IO
authors.lastname: Lawal
authors.forename: Nozipho E
authors.initials: NE
authors.lastname: Nyakale
authors.forename: Lerwine M
authors.initials: LM
authors.lastname: Harry
authors.forename: Thabo
authors.initials: T
authors.lastname: Lengana
authors.forename: Neo P
authors.initials: NP
authors.lastname: Mokgoro
authors.forename: Mariza
authors.initials: M
authors.lastname: Vorster
authors.forename: Mike M
authors.initials: MM
authors.lastname: Sathekge
mesh_terms: D055011:Ablation Techniques; D000328:Adult; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D013964:Thyroid Neoplasms / Q000097:blood* / Q000473:pathology / Q000601:surgery / Q000628:therapy*; D013965:Thyroidectomy; D013972:Thyrotropin / Q000097:blood*; D055815:Young Adult
chemical_list: D007457:Iodine Radioisotopes; D013972:Thyrotropin