title: Long-term survival and low effective cumulative radioiodine doses to achieve remission in patients with 131Iodine-avid lung metastasis from differentiated thyroid cancer.
abstract: OBJECTIVE
  To evaluate long-term survival and response to RAI treatment in patients with differentiated thyroid cancer (DTC) and 131Iodine-avid metastatic lung disease.
  
  
  METHODS
  A retrospective review of 639 DTC patients followed-up at the Hospital de Clínicas, Buenos Aires, Argentina, showed that 42 (6%) patients had lung metastasis, and 24 patients were included for analysis.
  
  
  RESULTS
  Seventeen were women, and 7 were men (F:M=2.4:1). Eighteen patients (75%) had PTC, and 6 (25%) had FTC. The median age at diagnosis was older than 45 years in 50%, and the median follow-up was 13 years. Good response to treatment (GRT: no evidence of disease or biochemical persistence without structural correlate) was observed in 46% of patients (all with diffuse postdose radioiodine uptake and no structural images higher than 1 cm in diameter); and 21% patients died from disseminated lung metastasis. Overall survival at 5 and 10 years was 100% and 88.4%, respectively. The Cox proportional hazard ratio showed that extrathyroidal invasion, positive uptake of 18-FDG, and metachronous diagnosis of the lung metastasis were variables that significantly predicted death. Those patients who had a GRT did with a mean effective cumulative RAI dose of 457.3±29.7 mCi 131I (range, 300-600 mCi 131I).
  
  
  CONCLUSIONS
  Lung metastasis showed a slow progression with a high long-term overall survival. The presence of synchronous lung metastasis, the absence of nodules larger than 1 cm, and the lack of uptake of FDG were predictive factors for an early response to treatment with RAI cumulative doses lower than 600 mCi 131I.
authors.affiliation: From the Division of Endocrinology, Hospital de Clínicas, University of Buenos Aires, Buenos Aires, Argentina.
authors.forename: Fabián
authors.initials: F
authors.lastname: Pitoia
authors.forename: Fernanda
authors.initials: F
authors.lastname: Bueno
authors.forename: Graciela
authors.initials: G
authors.lastname: Cross
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018265:Carcinoma, Papillary, Follicular / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007457:Iodine Radioisotopes / Q000008:administration & dosage / Q000627:therapeutic use*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000627:therapeutic use*; D011879:Radiotherapy Dosage; D012074:Remission Induction; D016019:Survival Analysis; D013964:Thyroid Neoplasms / Q000473:pathology / Q000532:radiotherapy*
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18