title: Long-term outcomes following low-dose radioiodide ablation for differentiated thyroid cancer.
abstract: BACKGROUND
  Randomized trials show that low-dose (1.1 GBq [30 mCi]) radioiodide (RAI) has efficacy equivalent to high-dose RAI (3.7 GBq [100 mCi]) in thyroid remnant ablation (TRA) for differentiated thyroid cancer. Long-term follow-up is required to ensure detection of late recurrences and to confirm equivalence in terms of survival end points. However, median follow-up duration within randomized trials is currently limited.
  
  
  METHODS
  We studied 53 patients undergoing TRA for differentiated thyroid cancer with long-term follow-up in the Thyroid Unit of The Royal Marsden Hospital (Sutton, United Kingdom).
  
  
  METHODS
  Patients were treated with TRA using low-dose (1.1 GBq) RAI.
  
  
  METHODS
  Disease-free survival, overall survival, and the incidence of second malignancies were measured. Multivariable analysis was used to determine clinical risk factors for failure to achieve TRA after low-dose RAI.
  
  
  RESULTS
  Median follow-up was 24 (range, 4-34) years. Low-dose RAI TRA was successful in 26 (49%) patients (successful ablation [SA] group), whereas 27 (51%) patients required further treatment (unsuccessful ablation [UA] group). Thirty-year disease-free survival was 92% in the SA group vs 87% in the UA group (P = .601). Thirty-year overall survival was 81% in the SA group vs 62% in the UA group (P = .154). Nine (17%) patients developed second malignancies (4 in the SA group and 5 in the UA group). Predictors of failure to achieve TRA with low-dose RAI were male sex and stage pT4 disease.
  
  
  CONCLUSIONS
  There is no evidence from long-term follow-up of our cohort that treatment outcomes are compromised for patients that fail TRA with low-dose RAI and subsequently receive high-dose RAI.
authors.affiliation: Thyroid Unit, Royal Marsden Hospital, Downs Road, Sutton, Surrey SM2 5PT, United Kingdom.
authors.forename: Liam
authors.initials: L
authors.lastname: Welsh
authors.forename: Ceri
authors.initials: C
authors.lastname: Powell
authors.forename: Brenda
authors.initials: B
authors.lastname: Pratt
authors.forename: Kevin
authors.initials: K
authors.lastname: Harrington
authors.forename: Chris
authors.initials: C
authors.lastname: Nutting
authors.forename: Clive
authors.initials: C
authors.lastname: Harmer
authors.forename: Kate
authors.initials: K
authors.lastname: Newbold
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000517:prevention & control; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control; D009367:Neoplasm Staging; D011446:Prospective Studies; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000627:therapeutic use*; D012727:Sex Characteristics; D016019:Survival Analysis; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000517:prevention & control / Q000601:surgery; D055815:Young Adult
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals