title: Post-surgical thyroid ablation with low or high radioiodine activities results in similar outcomes in intermediate risk differentiated thyroid cancer patients.
abstract: BACKGROUND
  In differentiated thyroid cancer (DTC) patients at intermediate risk of recurrences, no evidences are provided regarding the optimal radioactive iodine (RAI) activity to be administered for post-surgical thyroid ablation.
  
  
  METHODS
  This study aimed to evaluate the impact of RAI activities on the outcome of 225 DTC patients classified as intermediate risk, treated with low (1110-1850  MBq) or high RAI activities (≥3700  MBq).
  
  
  RESULTS
  Six to 18 months after ablation, remission was observed in 60.0% of patients treated with low and in 60.0% of those treated with high RAI activities, biochemical disease was found in 18.8% of patients treated with low and in 14.3% of patients treated with high RAI activities, metastatic disease was found in 21.2% of patients treated with low and in 25.7% of patients treated with high RAI activities (P=0.56). At the last follow-up (low activities, median 4.2 years; high activities, median 6.9 years), remission was observed in 76.5% of patients treated with low and in 72.1% of patients treated with high RAI activities, persistent disease was observed in 18.8% of patients treated with low and in 23.5% of patients treated with high RAI activities, recurrent disease was 2.4% in patients treated with low and 2.1% in patients treated with high RAI activities, deaths occurred in 2.4% of patients treated with low and in 2.1% of patients treated with high RAI activities (P=0.87).
  
  
  CONCLUSIONS
  Our study provides the first evidence that in DTC patients at intermediate risk, high RAI activities at ablation have no major advantage over low activities.
authors.affiliation: Section of Endocrinology and Metabolism, Department of Internal Medicine, Endocrinology and Metabolism and Biochemistry, University of Siena, Policlinico Santa Maria alle Scotte, Viale Bracci 1, 53100 Siena, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Castagna
authors.forename: Gabriele
authors.initials: G
authors.lastname: Cevenini
authors.forename: Alexandra
authors.initials: A
authors.lastname: Theodoropoulou
authors.forename: Fabio
authors.initials: F
authors.lastname: Maino
authors.forename: Silvia
authors.initials: S
authors.lastname: Memmo
authors.forename: Cipri
authors.initials: C
authors.lastname: Claudia
authors.forename: Valentina
authors.initials: V
authors.lastname: Belardini
authors.forename: Ernesto
authors.initials: E
authors.lastname: Brianzoni
authors.forename: Furio
authors.initials: F
authors.lastname: Pacini
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000532:radiotherapy / Q000601:surgery; D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000532:radiotherapy / Q000601:surgery; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects / Q000627:therapeutic use*; D053208:Kaplan-Meier Estimate; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011184:Postoperative Period; D012074:Remission Induction; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D013965:Thyroidectomy / Q000379:methods; D016896:Treatment Outcome
chemical_list: D007457:Iodine Radioisotopes