title: Long-term prognosis of differentiated thyroid cancer with lung metastasis in Korea and its prognostic factors.
abstract: BACKGROUND
  Distant metastasis, generally to lung and bone, is rare in differentiated thyroid carcinoma (DTC) and the prognosis is still elusive. We investigated long-term outcomes of lung metastasis in DTC patients and its prognostic factors.
  
  
  METHODS
  A retrospective review was performed of 4572 patients who underwent surgery for DTC from 1962 to 2009 at Seoul National University Hospital. Among them, 164 patients were identified with lung metastasis and 152 patients were enrolled in the final analysis. Poor prognosis was defined as progressive disease or death.
  
  
  RESULTS
  Of these 152 patients, 10- and 20-year survival rates were 85.0% and 71.0%, respectively. No evidence of disease, stable disease, progressive disease, and death was identified in 22.4%, 28.3%, 35.5%, and 13.8%, respectively, after 11 years of median follow-up (range 2-41 years). Older age at diagnosis (≥45 years), primary tumor size ≥2 cm, follicular thyroid cancer, metastasis diagnosed after initial evaluation or (131)I remnant ablation (late metastasis), multiple metastases other than lung, (131)I nonavidity, and the presence of macronodules (≥1 cm) were more frequent in poor prognoses. Cox proportional hazard ratio for progression-free survival showed that (131)I nonavidity was the only independent predictive factor for poor prognosis.
  
  
  CONCLUSIONS
  The prognosis of lung metastasis from DTC in Korea within this study was favorable. (131)I nonavidity, observed more frequently in late metastasis, was the only independent factor predicting poor prognosis.
authors.affiliation: 1 Department of Internal Medicine, Seoul National University , Seoul, Korea.
authors.forename: Sun Wook
authors.initials: SW
authors.lastname: Cho
authors.forename: Hoon Sung
authors.initials: HS
authors.lastname: Choi
authors.forename: Gye Jeong
authors.initials: GJ
authors.lastname: Yeom
authors.forename: Jung Ah
authors.initials: JA
authors.lastname: Lim
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Moon
authors.forename: Do Joon
authors.initials: DJ
authors.lastname: Park
authors.forename: June-Key
authors.initials: JK
authors.lastname: Chung
authors.forename: Bo Youn
authors.initials: BY
authors.lastname: Cho
authors.forename: Ka Hee
authors.initials: KH
authors.lastname: Yi
authors.forename: Young Joo
authors.initials: YJ
authors.lastname: Park
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000473:pathology*; D000328:Adult; D002277:Carcinoma / Q000601:surgery; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008175:Lung Neoplasms / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000473:pathology*; D016896:Treatment Outcome
chemical_list: D007457:Iodine Radioisotopes