title: Differentiated thyroid cancer presenting with distant metastases: a population analysis over two decades.
abstract: BACKGROUND
  Differentiated thyroid cancer (DTC) with distant metastases at presentation is uncommon; the prognosis of patients with this condition is more favorable than for other cancers. Demographic, clinical, and pathologic characteristics are described at a population level; factors associated with long-term disease-specific survival are identified.
  
  
  METHODS
  Patients were identified in the Surveillance, Epidemiology, and End Results (SEER) database between 1988 and 2009. They were divided into two groups: patients with distant metastases (met-DTC) and patients without distant metastases (DTC) at presentation. Data analyses were performed with chi square tests, ANOVA, Kaplan-Meier analysis, and binary logistic and Cox proportional hazards regression.
  
  
  RESULTS
  A total of 1,291 patients with met-DTC at diagnosis and 58,518 with DTC were included. The met-DTC rate was 2.2 %; compared to DTC, met-DTC patients were more often male (22.7 vs 41.3 %, respectively; p < 0.001) and older (mean 48.8 vs 62.7 years; p < 0.001). Patients with met-DTC were more likely not to have had surgery (23.3 vs 2.0 %; p < 0.001) or to have received radiation therapy (RAI) (66.8 vs 46.5 %; p < 0.001). Met-DTC tumors were larger (mean 41.0 vs 20.5 mm; p < 0.001). Independent factors associated with distant metastases were male gender, older age, single status, black and "other" races, follicular and Hurthle cell histology, larger tumors, and positive regional lymph nodes. Disease-specific survival was lower for met-DTC; this has not improved over the past two decades (p = 0.494). Independent factors associated with mortality included patient age ≥ 45 years, single status, follicular and Hurthle cell histologies, tumor size >4 cm, and not receiving surgery and/or RAI.
  
  
  CONCLUSIONS
  Overall, met-DTC is uncommon. Given the lack of survival improvement observed over the last two decades, novel treatments should be pursued aggressively for this subset of patients.
authors.affiliation: Milano-Bicocca University, via Cadore 48, 20900 Monza, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Goffredo
authors.forename: Julie A
authors.initials: JA
authors.lastname: Sosa
authors.forename: Sanziana A
authors.initials: SA
authors.lastname: Roman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D018714:Radiotherapy, Adjuvant; D018426:SEER Program; D016019:Survival Analysis; D013964:Thyroid Neoplasms / Q000175:diagnosis / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D013965:Thyroidectomy; D016896:Treatment Outcome; D055815:Young Adult