title: Clinical outcome of low-risk differentiated thyroid cancer patients after radioiodine remnant ablation and recombinant human thyroid-stimulating hormone preparation.
abstract: OBJECTIVE
  Recombinant human thyroid-stimulating hormone (rhTSH) has been approved in Europe as a preparation tool for radioiodine ablation of post-surgical thyroid remnants in patients with low-risk differentiated thyroid cancer (DTC). Published studies report that, both thyroid hormone withdrawal and rhTSH preparation result in similar rates of successful remnant ablation, but few studies have determined the effectiveness of rhTSH preparation on disease recurrence. We sought to determine the clinical outcome, considering both ablation success and disease recurrence, of low-risk DTC patients who underwent (131)I ablation.
  
  
  METHODS
  This retrospective study describes the clinical outcome of 100 patients treated with (131)I remnant ablation after preparation with rhTSH. After ablation, patients were classified as in complete remission, as having no evidence of persistent disease, or as having clinical recurrence on the basis of a subsequent diagnostic whole body scan with (131)I, stimulated thyroglobulin and cross-sectional imaging studies.
  
  
  RESULTS
  Overall assessment of ablation success was verified and obtained in 75% of patients (75/100). Considering only patients who underwent a diagnostic whole body scan and stimulated thyroglobulin without interfering anti-thyroglobulin antibody, complete ablation was obtained in 96% of patients (75/78). After a follow-up of about 4 years, 78 patients are in complete remission: 75 with initial ablation success and three who achieved a complete remission during subsequent follow-up. Among the remaining 22 patients, 21 have no clinical evidence of disease (NCED), indicating the inability to verify the complete remission or to detect residual disease, as in patients with positive thyroglobulin antibody, whereas one has persistent disease demonstrated only by stimulated thyroglobulin. No recurrences were observed. Of four patients initially classified as having persistent disease, one obtained a complete remission and two are now considered NCED.
  
  
  CONCLUSIONS
  Our data confirm the favourable outcome, with low rates of recurrence and persistent disease, of patients with low-risk DTC who underwent (131)I ablation after rhTSH. Moreover, our results compare favourably with those reported in the literature in patients prepared with rhTSH, but also in patients prepared with hormone withdrawal.
authors.affiliation: Radiotherapy and Nuclear Medicine Unit, Istituto Oncologico Veneto-IRCCS, Via Gattamelata 64, Padua, Italy. federica.vianello@ioveneto.it
authors.forename: F
authors.initials: F
authors.lastname: Vianello
authors.forename: R
authors.initials: R
authors.lastname: Mazzarotto
authors.forename: C
authors.initials: C
authors.lastname: Mian
authors.forename: O
authors.initials: O
authors.lastname: Lora
authors.forename: G
authors.initials: G
authors.lastname: Saladini
authors.forename: O
authors.initials: O
authors.lastname: Servodio
authors.forename: M
authors.initials: M
authors.lastname: Basso
authors.forename: G
authors.initials: G
authors.lastname: Pennelli
authors.forename: M R
authors.initials: MR
authors.lastname: Pelizzo
authors.forename: G
authors.initials: G
authors.lastname: Sotti
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy; D000231:Adenocarcinoma, Papillary / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002454:Cell Differentiation; D003131:Combined Modality Therapy; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011994:Recombinant Proteins / Q000627:therapeutic use*; D012189:Retrospective Studies; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy*; D013965:Thyroidectomy; D013972:Thyrotropin / Q000627:therapeutic use*; D016896:Treatment Outcome; D051598:Whole Body Imaging
chemical_list: D007457:Iodine Radioisotopes; D011994:Recombinant Proteins; D013972:Thyrotropin